Syphilis

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Background

Syphilis is an infectious venereal disease caused by the spirochete Treponema pallidum. Syphilis is transmissible by sexual contact with infectious lesions, from mother to fetus in utero, via blood product transfusion, and occasionally through breaks in the skin that come into contact with infectious lesions. If untreated, it progresses through 4 stages: primary, secondary, latent, and tertiary.

Syphilis has a myriad of presentations and can mimic many other infections and immune-mediated processes in advanced stages. Hence, it has earned the nickname “the great impostor.” The complex and variable manifestations of the disease prompted Sir William Osler to remark, “The physician who knows syphilis knows medicine.”

Many famous personages throughout history are thought to have suffered from syphilis, including Bram Stoker, Henry VIII, and Vincent Van Gogh. Since the discovery of penicillin in the mid-20th century, the spread of this once very common disease has been largely controlled, but efforts to eradicate the disease entirely have been unsuccessful.

Pathophysiology

Three genera of spirochetes cause human infection:

The particular spirochete responsible for syphilis is Treponema pallidum.

T pallidum is a fragile spiral bacterium 6-15 micrometers long by 0.25 micrometers in diameter. Its small size makes it invisible on light microscopy; therefore, it must be identified by its distinctive undulating movements on darkfield microscopy. It can survive only briefly outside of the body; thus, transmission almost always requires direct contact with the infectious lesion.

S yphilis is usually classified into 4 stages: primary, secondary, latent, and tertiary. It can be either acquired or congenital. That is, it can be transmitted either by intimate contact with infectious lesions (most common) or via blood transfusion (if blood has been collected during early syphilis), and it can also be transmitted transplacentally from an infected mother to her fetus.

Acquired syphilis

In acquired syphilis, T pallidum rapidly penetrates intact mucous membranes or microscopic dermal abrasions and, within a few hours, enters the lymphatics and blood to produce systemic infection. Incubation time from exposure to development of primary lesions, which occur at the primary site of inoculation, averages 3 weeks but can range from 10-90 days. Studies in rabbits show that spirochetes can be found in the lymphatic system as early as 30 minutes after primary inoculation, suggesting that syphilis is a systemic disease from the outset.

The central nervous system (CNS) is invaded early in the infection; during the secondary stage, examinations demonstrate that more than 30% of patients have abnormal findings in the cerebrospinal fluid (CSF). During the first 5-10 years after the onset of untreated primary infection, the disease principally involves the meninges and blood vessels, resulting in meningovascular neurosyphilis. Later, the parenchyma of the brain and spinal cord are damaged, resulting in parenchymatous neurosyphilis. Go to Neurosyphilis for complete information on this topic.

Regardless of the stage of disease and location of lesions, histopathologic hallmarks of syphilis include endarteritis (which in some instances may be obliterative in nature) and a plasma cell–rich infiltrate. Endarteritis is caused by the binding of spirochetes to endothelial cells, mediated by host fibronectin molecules bound to the surface of the spirochetes. The resultant endarteritis can heal with scarring in some instances.

The syphilitic infiltrate reflects a delayed-type hypersensitivity response to T pallidum, and in certain individuals with tertiary syphilis, this response by sensitized T lymphocytes and macrophages results in gummatous ulcerations and necrosis. Antigens of T pallidum induce host production of treponemal antibodies and nonspecific reagin antibodies. Immunity to syphilis is incomplete.

For example, host humoral and cellular immune responses may prevent the formation of a primary lesion on subsequent infections with T pallidum, but they are insufficient to clear the organism. This may be because the outer sheath of the spirochete is lacking immunogenic molecules, or it may be because of down-regulation of helper T cells of the TH1 class.[1, 2]

Primary syphilis is characterized by the development of a painless chancre at the site of transmission after an incubation period of 3-6 weeks. The lesion has a punched-out base and rolled edges and is highly infectious.

Histologically, the chancre is characterized by mononuclear leukocytic infiltration, macrophages, and lymphocytes. The inflammatory reaction causes an obliterative endarteritis. In this stage, the spirochete can be isolated from the surface of the ulceration or the overlying exudate of the chancre. Whether treated or not, healing occurs within 3-12 weeks, with considerable residual fibrosis.

Secondary syphilis develops about 4-10 weeks after the appearance of the primary lesion. During this stage, the spirochetes multiply and spread throughout the body. Secondary syphilis lesions are quite variable in their manifestations. Systemic manifestations include malaise, fever, myalgias, arthralgias, lymphadenopathy, and rash.

Widespread mucocutaneous lesions are observed over the entire body and may involve the palms, soles, and oral mucosae. Most often, the lesions are macular, discrete, reddish brown, and 5 mm or smaller in diameter; however, they can be pustular, annular, or scaling. All such lesions contain treponemes. Of these, wet mucous patches are the most contagious. Histologically, the inflammatory reaction is similar to but less intense than that of the primary chancre.

Other skin findings of secondary syphilis are condylomata lata and patchy alopecia. Condylomata lata are painless, highly infectious gray-white lesions that develop in warm, moist sites. The alopecia is characterized by patchy hair loss of the scalp and facial hair, including the eyebrows. Patients with this finding have been referred to as having a “moth-eaten” appearance. During secondary infection, the immune reaction is at its peak and antibody titers are high.

Latent syphilis is a stage at which the features of secondary syphilis have resolved, though patients remain seroreactive. Some patients experience recurrence of the infectious skin lesions of secondary syphilis during this period. About one third of untreated latent syphilis patients go on to develop tertiary syphilis, whereas the rest remain asymptomatic.

Currently, tertiary syphilis disease is rare. When it does occur, it mainly affects the cardiovascular system (80-85%) and the CNS (5-10%), developing over months to years and involving slow inflammatory damage to tissues. The 3 general categories of tertiary syphilis are gummatous syphilis (also called late benign), cardiovascular syphilis, and neurosyphilis.

Gummatous syphilis is characterized by granulomatous lesions, called gummas, which are characterized by a center of necrotic tissue with a rubbery texture. Gummas principally form in the liver, bones, and testes but may affect any organ. Histological examination shows palisaded macrophages and fibroblasts, as well as plasma cells surrounding the margins. Gummas may break down and form ulcers, eventually becoming fibrotic. Treponemes are rarely visualized or recovered from these lesions.

Cardiovascular syphilis occurs at least 10 years after primary infection. The most common manifestation is aneurysm formation in the ascending aorta, caused by chronic inflammatory destruction of the vasa vasorum, the penetrating vessels that nourish the walls of large arteries. Aortic valve insufficiency may result.

Neurosyphilis has several forms. If the spirochete invades the CNS, syphilitic meningitis results. Syphilitic meningitis is an early manifestation, usually occurring within 6 months of the primary infection. CSF shows high protein, low glucose, high lymphocyte count, and positive syphilis serology.

Meningovascular syphilis occurs as a result of damage to the blood vessels of the meninges, brain, and spinal cord, leading to infarctions causing a wide spectrum of neurologic impairments.

Parenchymal neurosyphilis includes tabes dorsalis and general paresis. Tabes dorsalis develops as the posterior columns and dorsal roots of the spinal cord are damaged. Posterior column impairment results in impaired vibration and proprioceptive sensation, leading to a wide-based gait.

Disruption of the dorsal roots leads to loss of pain and temperature sensation and areflexia. Damage to the cortical regions of the brain leads to general paresis, formerly called “general paresis of the insane,” which mimics other forms of dementia. Impairment of memory and speech, personality changes, irritability, and psychotic symptoms develop and may advance to progressive dementia.

The Argyll-Robertson pupil, a pupil that does not react to light but does constrict during accommodation, may be seen in tabes dorsalis and general paresis. The precise location of the lesion causing this phenomenon is unknown.

Congenital syphilis

Congenital syphilis, discussed briefly here, is a veritable potpourri of antiquated medical terminology. The treponemes readily cross the placental barrier and infect the fetus, causing a high rate of spontaneous abortion and stillbirth. Within the first 2 years of life, symptoms are similar to severe adult secondary syphilis with widespread condylomata lata and rash. “Snuffles” describes the mucopurulent rhinitis caused by involvement of the nasal mucosae.

Later manifestations of congenital syphilis include bone and teeth deformities, such as “saddle nose” (due to destruction of the nasal septum), “saber shins” (due to inflammation and bowing of the tibia), “Clutton’s joints” (due to inflammation of the knee joints), “Hutchinson’s teeth” (in which the upper incisors are widely spaced and notched), and “mulberry molars” (in which the molars have too many cusps).

Tabes dorsalis and general paresis may develop as in adults, with 8th cranial nerve deafness and optic nerve atrophy as well as a variety of other ophthalmologic involvement leading to blindness being additional features.

Go to Pediatric Syphilis for complete information on this topic.

Etiology

The cause of syphilis is infection with the spirochete T pallidum.T pallidum is solely a human pathogen and does not naturally occur in other species. T pallidum has, however, been cloned in Escherichia coli and has been used experimentally in rabbits.

Transmission of T pallidum occurs via penetration of the spirochetes through mucosal membranes and abrasions on epithelial surfaces. It is primarily spread through sexual contact but can be spread by exposure to blood products and transferred in utero. T pallidum is a labile organism that cannot survive drying or exposure to disinfectants; thus, fomite transmission (eg, from toilet seats) is virtually impossible.

Risk factors of syphilis include the following:

Epidemiology

United States statistics

Since reporting began in 1941, the incidence of primary and secondary syphilis in the United States has varied. The incidence dropped from 66.4 cases per 100,000 in 1947 to 3.9 cases per 100,000 in 1956 following the introduction of penicillin.

During the mid 1980s, however, this trend reversed. Increases in the use of intravenous (IV) drugs and crack cocaine, the exchange of sex for drugs, indiscriminate or anonymous sex, and the number of people with multiple sexual partners contributed to the turnaround. From 1986-1990, the rate of syphilis nearly doubled, reaching a peak of 53.8 cases per 100,000 population in 1990.

After 1990, the incidence decreased again; there were 53,000 reported cases (11,387 primary and secondary cases) in 1996, compared with 113,000 cases (33,962 primary and secondary cases) reported in 1992. In 2000, the number of syphilis cases reported was at an all-time low, with rates falling to 2.1 cases per 100,000 population. Increased awareness, aggressive screening, and emphasis on primary prevention contributed to the decrease.

Since 2000, however, the number of syphilis cases in the United States has slightly increased each year. The Centers for Disease Control and Prevention (CDC) reported that, from 2003-2004, the rate of primary and secondary syphilis increased 8%, from 2.5 to 2.7 cases per 100,000 population.[3] Preliminary 2007 syphilis data showed that the US rate of primary and secondary syphilis increased 12% between 2006 and 2007, from 3.3 to 3.7 cases per 100,000 population. A total of 11,466 cases were reported in 2007.[4]

Most of this increase has been noted in men, particularly in men who have sex with men (MSM).[3] The overall cases reported in women decreased. More than 80% of cases were reported in the southern United States. Trends for congenital syphilis cases closely parallel those for acquired syphilis cases in women, namely, a decreased incidence over the past decade.

International statistics

Internationally, the prevalence of syphilis varies by region. Syphilis remains prevalent in many developing countries and in some areas of North America, Asia, and Europe, especially Eastern Europe. The highest rates are in South and Southeast Asia, followed closely by sub-Saharan Africa. The third highest rates are in the regions of Latin America and the Caribbean.[5] In some regions of Siberia, as of 1999, prevalence was 1300 cases per 100,000 population.[6]

Age distribution for syphilis

Syphilis is most common during the years of peak sexual activity. Most new cases occur in men and women aged 15-40 years. In 2007, the rate of primary and secondary syphilis was highest in people aged 25-29 years (8.9 per 100,000).[7] An age-based breakdown of syphilis can be found on the CDC Web site.

The incidence of congenital syphilis has increased 3.7% from 2005-2006 after 14 years of decline in the United States (from 8.2 to 8.5 cases per 100,000 live births). Between 1996 and 2005, the yearly incidence of congenital syphilis decreased by an average of 14.1% (see the CDC Web site for more information).

Sex distribution for syphilis

Men are affected more frequently with primary or secondary syphilis than women. This difference has varied over time. Male-to-female ratios of primary and secondary syphilis increased from 1.6:1 in 1965 to nearly 3:1 in 1985. After, the ratio decreased, reaching a nadir in 1994-95.

Since 2002, the incidence of primary and secondary syphilis has risen 54% among men (from 3.7 per 100,000 in 2002 to 5.7 per 100,000 in 2006). Among women, the rates of primary and secondary syphilis remain lower. After a decade of declines, the overall prevalence of syphilis among females increased 11.1% between 2005 and 2006 (from 0.9 to 1 per 100,000). Males with primary and secondary syphilis outnumber females 6 to 1.[3] The recent increase in the male-to-female ratio is largely attributable to the increased rate of disease among MSM.

Studies of patients diagnosed with sexually transmitted diseases (STDs) demonstrate that men are screened for syphilis in emergency departments and health clinics more often than women. Although surveillance data based on risk behavior are not available, a separate CDC analysis suggests that approximately 64% of all adult primary and secondary syphilis cases in 2004 were among MSM, up from an estimated 5% in 1999. In 2007, 65% of new cases occurred in MSM, and there is a high rate of HIV co-infection.[7]

Sex-based trends in syphilis can be found on the CDC Web site.[8]

Prevalence of syphilis by race or ethnicity

In the United States, syphilis is more prevalent among persons of minority race and ethnicity. Non-Hispanic blacks are at higher risk for syphilis than non-Hispanic whites. In 1997, the reported incidence of syphilis among non-Hispanic blacks was 22 cases per 100,000 population. This was 44 times higher than the rate in non-Hispanic whites.[9] This ratio had declined to 8:1 by 2002, after implementation of a national plan to eliminate syphilis in the United States.

Although the reported prevalence of syphilis is somewhat higher among blacks than other ethnic groups,[10] this rate has declined significantly in recent years. From 2000-2003, the primary and secondary syphilis rate declined from 12 cases per 100,000 population to 7.8 cases per 100,000 population in this ethnic group. In 2002, 49.8% of all reported cases were in blacks, compared with 39.2% of cases in 2003.[11] In 2004, the rate among blacks was 5.6 times higher than the rate among whites.[3]

From 2005 to 2006, the incidence of primary and secondary syphilis increased in all racial and ethnic groups, with a 5.6% increase in non-Hispanic whites (from 1.8 to 1.9 per 100,000 population), 16.5% in African Americans (from 9.7 to 11.3 per 100,000 population), 12.5% among Hispanics (from 3.2 to 3.6 per 100,000 population), 18.2% among Asian/Pacific Islanders (from 1.1 to 1.3 per 100,000 population), and 37.5% among American Indian/Alaska Natives (from 2.4 to 3.3 per 100,000 population).

Data can be found on the CDC Web site.

Prognosis

The morbidity of syphilis ranges from the relatively minor symptoms of the primary stages of infection to the more significant constitutional systemic symptoms of secondary syphilis and the significant neurological and cardiovascular consequences of tertiary disease. Since latent syphilis can persist for years or decades, the manifestations of tertiary syphilis often occur much later in life, causing significant morbidity.

Although rarely seen by clinicians since the use of penicillin became widespread in the 1950s, the primary complications of syphilis in adults include neurosyphilis, cardiovascular syphilis, and gumma. Death resulting from syphilis continues to occur. One study found that of 113 recorded deaths resulting from sexually transmitted diseases, 105 were caused by syphilis, with cardiovascular and neurosyphilis accounting for the majority of these deaths.

These figures have continued to increase since the emergence of the AIDS epidemic, since genital ulcer diseases (including syphilis) are cofactors for the sexual transmission of HIV. Additionally, untreated patients who are HIV seropositive have an increased risk for rapid progression to neurosyphilis and for its complications. In addition, patients with HIV are at greater risk for development or relapse of early symptomatic neurosyphilis for up to 2 years after treatment with intramuscular or intravenous penicillin.

The morbidity and mortality of untreated syphilis must be estimated from the limited data available regarding its natural course. These data are largely from one retrospective study of autopsies and two prospective studies, most notably the famous Tuskegee Study of Untreated Syphilis in the Negro Male, which fell under serious ethical scrutiny in later years for exploiting a vulnerable patient population and not offering treatment for the disease when it became available after the study was underway.

These data indicate that approximately one third of patients left untreated will develop late complications, with 10% of the total developing cardiovascular syphilis; 6%, neurosyphilis; and 16%, gummatous syphilis. Mortality rates in general are greater among those affected, and late complications appear to occur more commonly in men than in women.[12, 13]

For patients diagnosed with either primary or secondary syphilis (without auditory/neurologic/ocular involvement), the prognosis is good following appropriate treatment. T pallidum remains highly responsive to the penicillins, and cure is likely.

For patients diagnosed with tertiary syphilis, the prognosis is less sanguine. Twenty percent of untreated patients with tertiary syphilis die of the disease, although a significant number of patients demonstrate cure with antibiotic therapy. With adequate treatment, 90% of patients with neurosyphilis have a clinical response.

Overall prognosis for tertiary syphilis depends on the duration and extent of disease activity, along with prior attempts to treat the disease. For example, prognosis for advanced symptomatic disease in cardiovascular syphilis is poor, unless it is treated with high doses of IV penicillin. In contrast, in patients with neurosyphilis complicated by optic atrophy and blindness, the ability to regain vision remains poor despite attempts with high-dose penicillin.

Congenital syphilis is the most serious outcome of syphilis in women. It has been shown that a higher proportion of infants are affected if the mother has untreated secondary syphilis, compared to untreated early latent syphilis. Since T pallidum does not invade the placental tissue or the fetus until the fifth month of gestation, syphilis causes late abortion, stillbirth, or death soon after delivery in more than 40% of untreated maternal infections.[14, 15] Neonatal mortality usually results from pulmonary hemorrhage, bacterial superinfection, or fulminant hepatitis.

For patients who are pregnant and have early syphilis, it is likely that the mother will deliver a child not infected by syphilis (assuming the mother was treated appropriately).

Patient Education

Patients who abuse IV drugs should be advised to avoid sharing needles and to use clean needles. Needle exchange programs are in place in some areas; however, the establishment and existence of these programs remain controversial in many communities.

It is also important to stress to patients the importance of compliance with their entire antibiotic course and follow-up visits.

As with all STDs, patient education must stress the importance of safer sexual practices and the need for prompt medical evaluation of chancres and other symptoms of STDs. All patients diagnosed with an STD should be screened for HIV infection.

Patients with syphilis should be counseled to notify their partners of infection and to inform them of the need to be treated. Information regarding management of sex partners infected with syphilis can be found at the CDC Web site.

For patient education information, see the Sexually Transmitted Diseases Center and Pregnancy and Reproduction Center, as well as Sexually Transmitted Diseases, Syphilis, Birth Control Overview, and Birth Control FAQs.

History

Because the manifestations of syphilis (particularly advanced syphilis) are nonspecific and may masquerade as many other diseases, the physician must keep a high index of suspicion regarding the possible diagnosis of syphilis. Rigorous attention to the time course of symptoms is required for proper staging.

Obtain a thorough sexual and social history, including the number of sexual partners, condom use, history of sexually transmitted diseases (STDs) in the patient and their partners, intravenous (IV) drug use, and exposure to blood products.

In children and infants, seek a maternal history, history of exposure to individuals with syphilis or blood products, and a history of sexual abuse.

Primary syphilis

Primary syphilis occurs within 3 weeks of contact with an infected individual. It manifests mainly on the glans penis in males and on the vulva or cervix in females. Ten percent of syphilitic lesions are found on the anus, fingers, oropharynx, tongue, nipples, fingers, or other extragenital sites. Regional nontender lymphadenopathy follows invasion.

Lesions (chancres) are usually solitary, raised, firm, red papules that can be several centimeters in diameter. The chancre erodes to create an ulcerative crater within the papule, with slightly elevated edges around the central ulcer (see the images below). It usually heals within 4-8 weeks, with or without therapy.


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Syphilis. These photographs depict the characteristic chancre observed in primary syphilis. Used with permission from Wisdom A. Color Atlas of Sexuall....


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Syphilitic chancre

Although genital chancres are frequently solitary, they may be multiple in some patients. Sometimes they appear as “kissing” lesions on opposing skin surfaces—for example, the labia (see the image below).


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Syphilis. This photograph depicts primary syphilis "kissing" lesions. Used with permission from Wisdom A. Color Atlas of Sexually Transmitted Diseases....

Secondary syphilis

Secondary syphilis manifests in various ways. It usually presents with a cutaneous eruption within 2-10 weeks after the primary chancre and is most florid 3-4 months after infection. The eruption may be subtle; 25% of patients may be unaware of skin changes. A localized or diffuse mucocutaneous rash (generally nonpruritic and bilaterally symmetrical) with generalized nontender lymphadenopathy is typical (see the image below). Patchy alopecia and condylomata lata may also be observed.


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Syphilis. These photographs show the disseminated rash observed in secondary syphilis. Used with permission from Wisdom A. Color Atlas of Sexually Tra....

Mild constitutional symptoms of malaise, headache, anorexia, nausea, aching pains in the bones, and fatigue often are present, as well as fever and neck stiffness. A small number of patients develop acute syphilitic meningitis and present with headache, neck stiffness, facial numbness or weakness, and deafness.

Other less-common manifestations include GI involvement, hepatitis, nephropathy, proctitis, arthritis, and optic neuritis.

Latent syphilis

Latency may last from a few years to as many as 25 years before the destructive lesions of tertiary syphilis manifest. Affected patients may recall symptoms of primary and secondary syphilis. They are asymptomatic during the latent phase, and the disease is detected only by serologic tests.

Latent syphilis is divided into early latent and late latent. The distinction is important because treatment for each is different. The early latent period is the first year after the resolution of primary or secondary syphilis. Asymptomatic patients who have a newly active serologic test after having a serologically negative test result within 1 year are also considered to be in the early latent period. Late latency syphilis is not infectious; however, women in this stage can spread the disease in utero.

A small percentage of infants infected in utero may have a latent form of infection that becomes apparent during childhood and, in some cases, during adult life. The earliest symptom that occurs prior to age 2 years is rhinitis (snuffles), soon followed by cutaneous lesions. After age 2 years, parents may note problems with the child’s hearing and language development and with vision. Facial and dental abnormalities may be noted.

Tertiary syphilis

Tertiary (late) syphilis is slowly progressive and may affect any organ. The disease is generally not thought to be infectious at this stage. Manifestations may include the following:

The lesions of benign tertiary syphilis usually develop within 3-10 years of infection. The typical lesion is a gumma, and patient complaints usually are secondary to bone pain, which is described as a deep boring pain characteristically worse at night. Trauma may predispose a specific site to gumma involvement.

CNS involvement may occur, with presenting symptoms representative of the area affected (ie, brain involvement [headache, dizziness, mood disturbance, neck stiffness, blurred vision] and spinal cord involvement [bulbar symptoms, weakness and wasting of shoulder girdle and arm muscles, incontinence, impotence]).

Some patients may present up to 20 years after infection with behavioral changes and other signs of dementia, which is indicative of neurosyphilis.

Congenital syphilis

Early congenital syphilis occurs within the first 2 years of life. Late congenital syphilis emerges in children older than 2 years.

Physical Examination

Conduct the physical examination with the manifestations of primary, secondary, and tertiary syphilis in mind. The lesions and exanthem of primary and secondary syphilis are infectious; thus, gloves and other relevant personal protective equipment must be worn.

Primary syphilis

The patient is typically afebrile. Symmetric rash is typical; however, the presence of overlying superinfection, scratching, or scaling may make the presentation atypical.

The chancre of primary syphilis usually begins as a single, painless papule that rapidly becomes eroded and indurated, with a surrounding red areola. The edge and base of the ulcer have a cartilaginous (buttonlike) consistency on palpation. Although classic chancres are not painful, they can become so if suprainfected with bacteria. Atypical primary lesions are common and may manifest as a papular lesion without subsequent ulceration or induration.

The primary lesion usually is associated with regional lymphadenopathy that may be unilateral or bilateral. Inguinal adenitis is usually discrete, firm, mobile, and painless, without overlying skin changes.

Chancres usually are located on the penis in heterosexual men, but in homosexual men, they may be found in the anal canal, mouth, or external genitalia. Common primary sites in women include the cervix and labia. Extragenital chancres occur most commonly above the neck, typically affecting the lips or oral cavity.

The lesion is highly infectious; when abraded, it exudes a clear serum containing numerous T pallidum organisms.

The healing primary chancre may remain present in 15-25% of patients.

Secondary syphilis

Secondary syphilis may present in many different ways but usually includes a localized or diffuse mucocutaneous rash and generalized nontender lymphadenopathy. The exanthem may be macular, papular, pustular, or mixed (see the images below).


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Secondary syphilis - Exanthem


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Initial lesions are bilaterally symmetric, pale red to pink (in light-skinned persons) or pigmented (in dark-skinned persons), discrete, round, nonpruritic macules that measure 5-10 mm in diameter and are distributed on the trunk and proximal extremities. After several days or weeks, red papular lesions 3-10 mm in diameter appear. These lesions often become necrotic and are distributed widely with frequent involvement of the palms and soles (see the image below).


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Syphilis. Palmar lesions observed in secondary syphilis. Used with permission from Wisdom A. Color Atlas of Sexually Transmitted Diseases. Year Book M....

Tiny papular follicular syphilids involving hair follicles may result in patchy alopecia. In addition to the classic moth-eaten alopecia, a diffuse alopecia also has been reported.

Reddish-brown papular lesions on the penis or anogenital area can coalesce into large elevated plaques up to 2-3 cm in diameter, known as condylomata lata (see the images below). Lesions usually progress from red, painful, and vesicular to “gun metal grey” as the rash resolves. Condylomata lata are highly infectious. They are sometimes confused with condylomata acuminata or venereal warts.


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These photographs illustrate examples of condylomata lata. The lesions resemble genital warts (condylomata acuminata). Fluids exuding from these lesio....


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Condylomata lata

From 10-15% of patients with secondary syphilis develop superficial mucosal erosions, usually painless, on the palate, pharynx, larynx, glans penis, vulva, or in the anal canal and rectum. These mucous patches are circular silver-gray erosions with a red areola. The erosions harbor treponemes and can transmit disease.

Ocular abnormalities, such as iritis, are a rare clinical finding, although anterior uveitis has been reported in 5-10% of patients with secondary syphilis. Less common findings include periostitis, arthralgias, meningitis, nephritis, hepatitis, proctitis, and ulcerative colitis. Go to Interstitial Keratitis for complete information on this topic.

Thirty percent of patients experience recurring symptoms after the primary or secondary stage of syphilis. Lesions are less numerous but are still infectious.

Tertiary syphilis

Symptomatic tertiary syphilis is the result of a chronic, progressive inflammatory process that eventually produces clinical symptoms years to decades after the initial infection. The liver and skeleton are commonly affected. Fever, jaundice, anemia, and nighttime skeletal pain are characteristic.

Gummatous syphilis is characterized by coalescent granulomatous lesions, called gummas, that usually affect skin, bone, and mucous membranes but may involve any organ system, often causing local destruction of the affected organ system (see the image below). Cutaneous gummas are indurated, nodular, papulosquamous or ulcerative lesions that form characteristic circles or arcs with peripheral hyperpigmentation. They may mimic other granulomatous ulcerative lesions and may be histologically indistinguishable from them.


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Syphilis. These photographs show close-up images of gummas observed in tertiary syphilis. Used with permission from Wisdom A. Color Atlas of Sexually ....

Although gummas may be identified on the skin, in the mouth, and in the upper respiratory tract, they appear most commonly on the leg just below the knee. Gummas may be multiple or diffuse but usually are solitary lesions that range from less than 1 cm to several centimeters in diameter. They are generally asymmetric and grouped together.

Cardiovascular syphilis usually involves the aorta, though other large arteries may be affected as well. Invading treponemes cause scarring of the tunica media. Over many years, the inflammatory scarring weakens the aortic wall, leading to aneurysm formation, which causes incompetence of the aortic valve and narrowing of the coronary ostia.

The most common clinical finding on cardiovascular examination is a diastolic murmur with a tambour quality, secondary to aortic dilation with valvular insufficiency.

Neurosyphilis is caused by invasion of T pallidum into the CNS. It manifests as an insidious but progressive loss of mental and physical functions and is accompanied by mood alterations.

Neurosyphilis may be either asymptomatic or symptomatic. In asymptomatic neurosyphilis, no signs or symptoms are present, but CSF abnormalities are demonstrable, including possible pleocytosis, elevated protein, decreased glucose, or a reactive CSF Venereal Disease Research Laboratory (VDRL) test.

Symptomatic neurosyphilis produces various clinical syndromes that develop in approximately 5% of patients with syphilis who remain untreated. It may manifest in the following three forms:

Syphilitic meningitis usually develops within 6 months to several years of initial infection, and patients present with typical symptoms of meningitis, including headache, nausea and vomiting, and photophobia, but are typically afebrile. Patients may exhibit cranial nerve abnormalities.

Meningovascular syphilis manifests 5-10 years after infection and is the result of endarteritis, which affects small blood vessels of the meninges, brain, and spinal cord. Patients may present with CNS vascular insufficiency or outright stroke. The most common presentation of meningovascular syphilis (diffuse inflammation of the pia and arachnoid along with widespread arterial involvement) is an indolent stroke syndrome involving the middle cerebral artery.

Cranial nerve palsies and pupillary abnormalities occur with basilar meningitis.

Parenchymatous neurosyphilis results from direct parenchymal CNS invasion by T pallidum and is usually a late development (15-20 years after primary infection). It includes general paresis and tabes dorsalis. Paretic syphilis is the result of widespread parenchymal invasion that causes individual cell death and brain atrophy. Tabes dorsalis is the result of damage to the sensory nerves in dorsal roots, producing ataxia and loss of pain sensation, proprioception, and deep tendon reflexes in joints.

Patients with parenchymatous neurosyphilis present with ataxia; incontinence; paresthesias; and loss of position, vibratory, pain, and temperature sensations. Paresis and dementia, with changes in personality and intellect, may develop.

Tabes dorsalis presents with signs of demyelination of the posterior columns, dorsal roots, and dorsal root ganglia (eg, ataxic wide-based gait and foot slap, areflexia and loss of position, deep pain and temperature sensations). Deep ulcers of the feet can result from loss of pain sensation.

Argyll Robertson pupil, which occurs almost exclusively in neurosyphilis, is a small irregular pupil that reacts normally to accommodation but not to light.

Rare findings include iritis, with possible adhesion of the iris to the anterior lens, producing a fixed pupil (not to be confused with Argyll Robertson pupil).

Go to Neurosyphilis for complete information on this topic.

Congenital syphilis

The manifestations of untreated congenital syphilis can be divided into those that are expressed prior to age 2 years (early) or after age 2 years (late).

Clinical evidence of early congenital syphilis is similar to that of secondary syphilis in adults.[16] Early signs and symptoms include development of a diffuse rash, characterized by extensive sloughing of the epithelium, particularly on the palms, soles, and skin around the mouth and anus. The rash has a higher probability of being atypical and can be vesicular or bullous instead of the characteristic reddish brown macular rash.

A compilation of early clinical presentations of congenital syphilis in 9 studies involving a total of 212 infants included abnormal bone radiographs (61%); hepatomegaly (51%); splenomegaly (49%); petechiae (41%); other skin rashes (35%); anemia (34%); lymphadenopathy (32%); jaundice (30%); pseudoparalysis, often due to pain secondary to osteochondritis (28%); and snuffles (23%).

A classic mucocutaneous sign is depressed linear scars radiating from the orifice of the mouth (perioral fissures), termed rhagades (Parrot lines).

Additional symptoms of early congenital syphilis include the following:

The clinical manifestations of untreated congenital neurosyphilis present in 25% of patients older than age 6 years and correspond to those of adult neurosyphilis. Late congenital syphilis mainly manifests as neurologic symptoms. Cardiovascular abnormalities are rare. Findings include the following[17] :

Go to Pediatric Syphilis for complete information on this topic.

Complications

Complications of syphilis may include the following:

Approach Considerations

T pallidum cannot be cultivated in vitro and is too small to be seen under the light microscope. Serologic testing is considered the standard method of detection for all stages of syphilis. (Note, however, that serologic tests cannot be used to differentiate the different species of the treponeme family—for example, yaws.)

In suspected acquired syphilis, first perform nontreponemal serology screening using the Venereal Disease Research Laboratory (VDRL), rapid plasma reagin (RPR), or the recently developed ICE Syphilis recombinant antigen test.

Sensitivity of the VDRL and RPR tests are estimated to be 78-86% for detecting primary syphilis, 100% for detecting secondary syphilis, and 95-98% for detecting tertiary syphilis. Specificity ranges from 85-99% and may be reduced in individuals who have coexisting conditions (ie, collagen vascular disease, pregnancy, intravenous drug use, advanced malignancy, tuberculosis, malaria, viral and rickettsial diseases).[19]

VDRL test results turn positive 1-2 weeks after chancre formation. Nontreponemal tests usually become nonreactive with time after treatment. However, in some patients, nontreponemal antibodies can persist, sometimes for the life of the patient.[20]

Because of the possibility of false-positive results, confirmation for any positive or equivocal nontreponemal test result should follow with a treponemal test, such as the fluorescent treponemal antibody-absorption (FTA-ABS), quantitative VDRL/RPR, microhemagglutination assay T pallidum (MHA-TP), T pallidum hemagglutination (TPHA), and T pallidum particle agglutination (TPPA) tests.[21, 22] Treponemal enzyme immunoassay (EIA) for immunoglobulin G (IgG) and immunoglobulin M (IgM) may be performed.

FTA-ABS is commonly used as a confirmatory test following positive VDRL or RPR test findings. FTA-ABS has a sensitivity of 84% for detecting primary syphilis infection and almost 100% sensitivity for detecting syphilis infection in other stages. Its specificity is 96%.[19]

Some labs have adopted reverse sequence screening in order to reduce time, labor, and costs. Reverse screening test sera first by automatable treponemal enzyme and chemiluminescence immunoassays (EIA/CIA), followed by testing of reactive sera with a nontreponemal test. Results of the first direct comparison of traditional and reverse screening suggest reverse screening may not be as inferior to traditional testing as previously thought. Six out of 1000 patients tested were falsely reactive by reverse screening, compared to none by traditional testing. However, reverse screening identified 2 patients with possible latent syphilis that were not detected by RPR.[23] The CDC recommends traditional testing, but if reverse screening is used all sera that produce reactive EIA/CIA results should be reflexively tested with a quantitative nontreponemal test. Sera with discordant results should be reflexively tested with a confirmatory TPPA test.

Testing must be performed more than once in patients diagnosed with latent syphilis in order to exclude laboratory error.

Dark-field microscopy is essential in evaluating moist cutaneous lesions, such as the chancre of primary syphilis or the condyloma lata of secondary syphilis (see the image below).


View Image

Syphilis. This is a dark-field micrograph of spirochetes. Used with permission from Murray P et al. Medical Microbiology. 2nd ed. Mosby; 1994.

When dark-field microscopy is not available, direct immunofluorescence staining of fixed smears (direct fluorescent antibody T pallidum [DFA-TP]) is an option. Both procedures detect the causative organism at a rate of approximately 85-92%.

Slit-lamp examination and ophthalmic assessment can be used to differentiate between acquired and congenital syphilis (presence of interstitial keratitis) in patients with latent infection of uncertain duration.

Diagnosis of neurosyphilis can be challenging. The VDRL test for cerebrospinal fluid (VDRL-CSF) is highly specific but has low sensitivity. Therefore, the diagnosis of neurosyphilis usually depends on a combination of reactive serologic test results, CSF cell count, CSF protein, and clinical manifestations with or without a reactive VDRL-CSF. Some specialists recommend performing an FTA-ABS test on CSF. The CSF FTA-ABS is less specific for neurosyphilis than the VDRL-CSF, but it is highly sensitive.[20]

Infants with suspected congenital syphilis and positive VDRL or FTA-ABS test results can undergo 19S IgM FTA-ABS serologic testing (maternal IgM is not passed to the fetus in utero). However, the false-negative rate is 35%, and the false-positive rate is 10%. The Captia Syphilis-M enzyme-linked immunosorbent assay is an option.

The United States Preventive Services Task Force (USPSTF) has reaffirmed its recommendation for screening all pregnant women for syphilis infection at the first prenatal visit. High-risk women (eg, uninsured women, women living in poverty, sex workers, illicit drug users, those with other sexually transmitted diseases, those living in communities with high syphilis morbidity) should also be tested in the third trimester and at delivery.

If the test results are positive for syphilis, the treatment of choice is parenteral benzathine penicillin G. Dosage and the length of treatment depend on the stage and clinical manifestations of the disease.[24]

Patients with confirmed syphilis infections should be tested for other sexually transmitted diseases, including HIV.

According to the 2010 CDC STD guidelines, there is insufficient evidence to establish whether infants who have congenital syphilis and whose mothers are coinfected with HIV need different evaluation, treatment, or follow-up for syphilis than is recommended for all infants.[18]

Imaging Studies

Imaging studies should be performed depending on the organ system involved. For example, granulomatous disease can be seen on computed tomography (CT).

Obtain chest radiography in patients with tertiary syphilis to screen for aortic dilatation. Linear calcification of the ascending aorta on chest films suggests asymptomatic syphilitic aortitis. Radiologic abnormal findings commonly seen with advanced gummas of bone include periostitis, destructive osteitis, or sclerosing osteitis.

Angiography may be useful to distinguish between abdominal aneurysms of syphilitic versus arteriosclerotic origin. About 10% of syphilitic aneurysms occur superior to the renal arteries, while arteriosclerotic abdominal aneurysms usually are found inferior to the renal arteries.

CT scanning and magnetic resonance imaging (MRI) of the head and body may be used to document the complications of tertiary syphilis.

Lumbar Puncture

Invasion of the central nervous system (CNS) by treponemes occurs in 30-40% of patients with primary or secondary syphilis; however, no studies show this to be a predictor of poor neurologic outcome. According to the 2010 CDC STD treatment guidelines, CSF laboratory abnormalities are common in persons with early syphilis, even when clinical neurological findings are absent. If clinical evidence of neurological involvement is found, a CSF examination should be performed.[18]

Current guidelines in clinical infectious diseases state that physicians should evaluate CSF in individuals with latent syphilis of unknown duration or with late latent syphilis if (1) treatment fails, (2) neurologic or ocular symptoms are present; or (3) the patient has underlying HIV infection. LP is only relatively indicated in patients with high titers on serological tests (≥1:32). It is also indicated if there are other changes indicative of active syphilis (eg, gumma, aortitis).

LP should be performed on patients suspected of having neurosyphilis with no contraindication. CSF examination is the only means by which the occurrence of asymptomatic neurosyphilis in latent syphilis can be excluded.

Examination of the CSF should include the VDRL test, cell count, and protein level. Abnormalities of any of these measurements combined with a suggestive history and examination strongly indicate the presence of neurosyphilis. Derangements of these values are consistently found in neurosyphilis. A positive VDRL test result indicates active syphilis. A positive polymerase chain reaction (PCR) test finding is sensitive in detecting past invasion of the CNS but does establish whether the T pallidum organisms are still alive.

Histologic Findings

The primary lesion of syphilis is a chancre. Histologically, skin and mucosal lesions show a perivascular and perijunctional infiltrate of lymphocytes, plasma cells, and macrophages. At times, capillary endothelial proliferation and subsequent obliteration of small blood vessels may be appreciable. Focal erosion or ulceration is common.

The inflammatory reaction of secondary syphilis is histologically similar to that of the primary chancre but is less intense. Skin lesions are typified by a “lichenoid-psoriasiform” configuration with a perijunctional infiltrate of lymphocytes, histiocytes, and plasmacytes (see the image below). Often the histiocytic component of the infiltrate is prominent, and thus the biopsy may assume a “lichenoid-granulomatous” configuration.


View Image

Lues hematoxylin and eosin stain. Histopathological examination shows a lichenoid infiltrate that is stereotypical of the secondary stage of syphilis.....

Small numbers of neutrophils may be included in the perijunctional infiltrate, and neutrophils may also be present in an expanded overlying stratum corneum. Organisms are readily demonstrable using T pallidum immunoperoxidase staining during the secondary stage (see the image below).


View Image

Lues TP stain. Immunoperoxidase staining for T pallidum highlights many slender coiled organisms residing in the perijunctional zone. Occasionally, or....

In tertiary syphilis, histological examination shows gummas consisting of granulomatous inflammation with central necrosis flanked by plump or palisaded macrophages and fibrocytes surrounded by large numbers of mononuclear leukocytes, including many plasma cells. Treponemes are rare in these lesions and typically cannot be cultured or visualized.

Aortitis reveals inflammatory scarring of the tunica media, secondary to obliterative endarteritis of the vasa vasorum. Uneven loss of the medial elastic fibers and muscle cells may be evident. See the images below.

Approach Considerations

Penicillin is the treatment of choice for treating syphilis. According to the Centers for Disease Control and Prevention (CDC) (see current CDC recommendations), patients with known penicillin allergies should undergo penicillin allergy skin testing and penicillin desensitization, if necessary.[25] The 2010 CDC STD treatment guidelines recommend desensitization in penicillin-allergic pregnant women, followed by treatment with penicillin.[18]

Clinical and serologic conversions are the endpoints of medical treatment for syphilis. Follow-up Venereal Disease Research Laboratory (VDRL) test levels should be obtained to document treatment efficacy.

Antibiotic Therapy

Penicillin

Penicillin was established as an effective treatment for syphilis before the widespread use of randomized clinical trials.[18] The treatment guidelines published by the CDC (see current CDC recommendations) are based largely on uncontrolled trials and expert opinion. Guidelines are based on staging, with later stages requiring longer courses of treatment due to the slower rate of bacterial replication.

Penicillin remains the mainstay of treatment and the standard by which other modes of therapy are judged.[26] The 2010 CDC STD treatment guidelines support the use of penicillin as the preferred drug for treating all stages of syphilis.[18] Penicillin is the only therapy used widely for neurosyphilis, congenital syphilis, or syphilis during pregnancy. Rarely, T pallidum has been found to persist following adequate penicillin therapy; however, there is no indication that the organism has acquired resistance to penicillin.

The following regimens are recommended for penicillin treatment:

In patients with a history of penicillin allergy, skin testing is recommended. Patients who are skin test negative can receive conventional treatment with penicillin; skin test positive patients should be desensitized in the hospital. Make every effort to document penicillin allergy before choosing an alternative treatment, because the efficacy of alternative regimens is questionable in all stages of syphilis. Many treatment failures have been reported.

According to the 2010 CDC STD guidelines, no treatment regimens for syphilis have been shown to be more effective in preventing neurosyphilis in patients who are HIV positive than the syphilis regimens recommended for patients who are HIV negative. Careful monitoring after therapy is required.[18]

Alternatives to penicillin

As stated in the 2010 CDC guidelines, several therapies exist that might be effective in nonpregnant, penicillin-allergic patients with primary or secondary syphilis.[18]

Tetracycline, erythromycin, and ceftriaxone[27] have shown antitreponemal activity in clinical trials; however, they currently are recommended only as alternative treatment regimens in patients allergic to penicillin. The 2010 CDC guidelines suggest that a 10- to 14-day trial of ceftriaxone is effective for treating early syphilis, although the optimal dose and duration have not been established. Doxycycline and tetracycline have been used for many years.[18]

Azithromycin has also been studied. A meta-analysis of randomized clinical trials comparing azithromycin to benzathine penicillin G for early syphilis was published in 2008 showing favorable results for azithromycin.[28] The CDC 2010 STD treatment guidelines cite the effectiveness of azithromycin in treating early syphilis. However, there are documented cases of treatment failure due to azithromycin-resistant mutations in T pallidum in several areas of the United States. Therefore, azithromycin should be used only when the use of penicillin or doxycycline is not feasible. Its use in men who have sex with men (MSM) or pregnant women is contraindicated.[18] A 2010 study by Hook et al showed a single dose of azithromycin (2 g PO) to be equivalent to the treatment of choice, benzathine penicillin G (2.4 million units IM) in patients with early syphilis without HIV. Serological cure after 6 months of follow-up was not significant between the 2 treatments, although azithromycin recipients had a higherincidence of adverse effects (mostly self-limited gastrointestinal symptoms).[29]

A larger, multicenter trial is needed to confirm these results before this treatment can be recommended. Azithromycin treatment failures have been reported by the CDC.[30]

Jarisch-Herxheimer reaction

Following the initiation of treatment, the dying treponemes release inflammatory molecules that trigger a cytokine cascade possibly leading to a response known as the Jarisch-Herxheimer reaction. Symptoms include myalgias, fever, headache, and tachycardia, sometimes with exacerbation of whatever current syphilitic lesions are manifested (eg, rash or chancre).

The reaction is common, develops within several hours after beginning antibiotic treatment, and usually clears within 24 hours after onset. Its exact etiology is unclear, although it may be due to an immunological reaction to the rupture of spirochetes.

Management of this reaction often involves symptomatic treatment (eg, with antipyretics and analgesics) and observation. In pregnant women, treatment may induce early labor or cause fetal distress. Patients should be informed of the possibility of this reaction before undergoing antibiotic therapy. As stated in the CDC 2010 STD treatment guidelines, although the Jarisch-Herxheimer reaction might induce obstetric complications such as early labor or fetal distress, this risk should not preclude or delay therapy for syphilis.[18] Women are advised to seek obstetric care after treatment if they notice any fever, uterine contractions, or a decrease in fetal movement.[18]

Procaine toxicity

Some patients experience severe anxiety and other psychological disturbances after the administration of procaine penicillin. Fever, hallucinations, hyperventilation, and convulsions characterize the reaction. Circulatory collapse is occasionally reported.

Resuscitation and supportive care are necessary in severe cases; however, most reactions are mild, requiring only reassurance or symptomatic relief. Symptoms usually dissipate within 30 minutes.

Surgical Care

Surgical care is reserved for treating the complications of tertiary syphilis (eg, aortic valve replacement).

Prevention of Syphilis

The primary goal of prevention is to limit the spread of syphilis. This entails counseling patients to use safe sex practices and advising patients who abuse intravenous (IV) drugs to never share needles and to use clean needles. Notification and treatment of sexual partners and exposed drug partners are paramount. Prevention also entails educating health care workers to use universal precautions when treating all patients.

Studies of primary screening for syphilis in clinics and emergency departments are favorable for screening of high-risk, inner-city populations. Routine screening is advocated for all at-risk mothers.

Two reports from 2009 indicate that circumcision does not help prevent the transmission of syphilis, although circumcision may help prevent the transmission of viral sexually transmitted diseases.[31, 32]

Consultations

Consultation with an infectious diseases specialist may be required for difficult or complex cases of syphilis. Consult with a dermatologist, vascular surgeon, ophthalmologist, or neurologist should also be obtained as necessary to assist with the variable presentations of syphilis.

Additionally, the CDC, the World Health Organization (WHO), and Morbidity and Mortality Weekly Report (MMWR) are excellent updated references. Syphilis may be reportable to public health authorities in some jurisdictions.

Long-Term Monitoring

Inpatient care is generally reserved for complications of late syphilis.

Monitor patients with syphilis to ensure adequacy of treatment. The Clinical Effectiveness Group notes that follow-up visits in patients with syphilis should be performed at 3-, 6-, and 12-month intervals. Patients with HIV infection or patients treated with a nonpenicillin regimen should be monitored for life.

Generally speaking, therapy is considered a failure if the signs and symptoms of syphilis return. This occurs when the titer of the nontreponemal test increases 4-fold or a 4-fold decrease from the initial VDRL titer does not occur within 1 year.

However, clearly defined criteria regarding treatment failure are lacking. In their literature review, Augenbraun and Rolfs found that 15-25% of patients treated for syphilis do not have a 4-fold decrease in titers over a 3-month period, and some do not have a decrease for 6 months or longer.[33] Information is lacking on whether these patients are at higher risk for progression. Currently accepted guidelines are as follows:

Recommendations for specific patient subsets are as follows.

Patients with treated primary or secondary syphilis

Patients treated for primary and secondary syphilis should have follow-up VDRL testing at 3, 6, and 12 months after treatment. Patients with HIV should be monitored closely, as they are known to have more rapid progression of disease. Most patients with primary syphilis who are treated adequately have a nonreactive VDRL within 1 year, and almost all patients treated for secondary syphilis have a negative VDRL result within 2 years. A small minority of patients remain seropositive in spite of successful treatment.

According to the 2010 CDC STD guidelines, HIV-infected individuals should be assessed clinically and serologically for treatment failure at 3, 4, 9, 12, and 24 months post therapy.[18]

If the VDRL titer of 1:8 or more fails to fall at least 4 fold within 12 months or if the titer starts to rise, consider more intensive retreatment, and examine the cerebrospinal fluid (CSF). If all clinical and serologic examinations remain satisfactory for 2 years following treatment, the patient can be reassured that cure is complete, and no further follow-up care is needed.

Patients with latent syphilis

Perform quantitative reagin testing for up to 2 years. Schedule annual follow-up visits for an indefinite period of time for patients with persistently positive serologic tests.

The 2010 CDC STD treatment guidelines state that HIV-infected individuals with latent syphilis should receive the same stage-specific treatment as recommended for HIV-negative individuals.[18]

Patients with benign tertiary or cardiovascular syphilis

Patients should be observed by the physician for the rest of their lives to monitor for complications.

Patients with neurosyphilis

Patients with neurosyphilis should have follow-up at 6-month intervals for at least 3 years with physical examinations, CSF evaluation (eg, cell count, protein, reagin titer), and serologic testing.

Go to Neurosyphilis for complete information on this topic.

Pregnant patients with syphilis

Pregnant women treated for syphilis should have monthly VDRL testing for the duration of their pregnancy.

Medication Summary

The goal of pharmacotherapy is to eradicate the causative organism of syphilis, T pallidum. Penicillin is the mainstay of treatment, the standard by which other modes of therapy are judged, and the only therapy that has been used widely for neurosyphilis, congenital syphilis, or syphilis during pregnancy.

Penicillin

The drug of choice is parenteral penicillin G for all stages of syphilis. According to the 2010 CDC STD treatment guidelines, penicillin G is the only therapy that is clinically documented to be effective against syphilis during pregnancy.[18] Since the dividing time of T pallidum is slow (days), penicillin G benzathine is the only penicillin effective for single-dose therapy because it is in depo form and levels remain therapeutic in the blood for up to 30 days. Avoiding Bicillin C-R (combination procaine and benzathine), which remains in blood for only 7 days, is essential.

On rare occasions, T pallidum has been found to persist after adequate penicillin therapy; however, no indication exists that T pallidum has acquired resistance to the drug.

According to the Centers for Disease Control and Prevention (CDC; see current CDC recommendations), patients with known penicillin allergies should undergo penicillin allergy skin testing and penicillin desensitization, if necessary.[25]

Alternatives to penicillin

Since T pallidum resistance to penicillin has not emerged, the primary need for alternative drugs in treating syphilis is reserved for penicillin-allergic patients.

Researchers are studying the efficacy of ceftriaxone and azithromycin in treating syphilis. Central nervous system (CNS) penetration and its similarity to penicillin support the use of ceftriaxone in the treatment of syphilis. Studies are presently inconclusive, and CDC guidelines neither support nor refute its use. Given the limited data available to support its efficacy, prudence dictates a 5- to 7-day course of treatment for early syphilis.

The long half-life of azithromycin and its clinical efficacy in vitro against syphilis support its use in treating early syphilis. At present, however, clinical data remain insufficient to recommend its use.

No good evidence indicates that the non–beta-lactam antibiotics, which are used as alternatives to penicillin, are clinically effective in syphilis. Erythromycin has been associated with high failure rates. Doxycycline may be an option for patients who refuse parenteral therapy.

Penicillin G benzathine (Bicillin L-A)

Clinical Context:  Benzathine penicillin G is the first-line agent for primary and secondary syphilis infection. It is a spirocheticide with in vivo activity against T pallidum. It interferes with cell wall mucopeptide synthesis during replication.

Penicillin G procaine

Clinical Context:  Penicillin G procaine is the first-line agent for treating late latent syphilis.

Doxycycline (Doryx, Vibramycin)

Clinical Context:  Doxycycline is used as alternative therapy for syphilis infection. It inhibits bacterial growth by binding to the 30S ribosomal unit, preventing protein synthesis.

Tetracycline (Sumycin)

Clinical Context:  Tetracycline is used as alternative therapy for syphilis infection. It inhibits bacterial growth by binding to the 30S ribosomal unit, preventing protein synthesis.

Erythromycin (E.E.S., E-Mycin)

Clinical Context:  Erythromycin inhibits bacterial growth, possibly by blocking dissociation of peptidyl tRNA from ribosomes, causing RNA-dependent protein synthesis to arrest. It is used for treatment of staphylococcal and streptococcal infections. In children, age, weight, and severity of infection determine proper dosage. When twice-daily dosing is desired, half of the total daily dose may be taken q12h. For more severe infections, double the dose.

Ceftriaxone (Rocephin)

Clinical Context:  Ceftriaxone is an alternative agent for penicillin-allergic patients. It is a third-generation cephalosporin with broad-spectrum, gram-negative activity; it has lower efficacy against gram-positive organisms and higher efficacy against resistant organisms. It arrests bacterial growth by binding to one or more penicillin binding proteins.

Azithromycin (Zithromax)

Clinical Context:  Azithromycin acts by binding to the 50S ribosomal subunit of susceptible microorganisms and blocks dissociation of peptidyl tRNA from ribosomes, causing RNA-dependent protein synthesis to arrest. Nucleic acid synthesis is not affected.

Azithromycin concentrates in phagocytes and fibroblasts as demonstrated by in vitro incubation techniques. In vivo studies suggest that concentration in phagocytes may contribute to drug distribution to inflamed tissues. This drug is used to treat mild-to-moderate microbial infections.

Class Summary

Empiric antimicrobial therapy must be comprehensive and should cover all likely pathogens in the context of the clinical setting.

Probenecid

Clinical Context:  Probenecid inhibits tubular secretion of penicillin and usually increases penicillin plasma levels by any route the antibiotic is administered. A 2- to 4-fold elevation has been demonstrated for various penicillins. Probenecid is used as an adjunct to penicillin in late latent and neurosyphilis.

Class Summary

Uricosuric agentsare used to increase serum concentration of certain antibiotics and other drugs.

Author

Brian Euerle, MD, FACEP, Associate Professor, Department of Emergency Medicine, Director of Emergency Ultrasound Program, University of Maryland School of Medicine

Disclosure: Nothing to disclose.

Coauthor(s)

Daniel J Hogan, MD, Clinical Professor of Internal Medicine (Dermatology), Nova Southeastern University College of Osteopathic Medicine; Investigator, Hill Top Research, Florida Research Center

Disclosure: Nothing to disclose.

Eric L Weiss, MD, DTM&H, Medical Director, Office of Service Continuity and Disaster Planning, Fellowship Director, Stanford University Medical Center Disaster Medicine Fellowship, Chairman, SUMC and LPCH Bioterrorism and Emergency Preparedness Task Force, Clinical Associate Professor, Department of Surgery (Emergency Medicine), Stanford University Medical Center

Disclosure: Nothing to disclose.

Joseph J Sachter, MD, FACEP, Consulting Staff, Department of Emergency Medicine, Muhlenberg Regional Medical Center

Disclosure: Nothing to disclose.

Maria M Diaz, MD, Staff Physician, Department of Emergency Medicine, Parkland Medical Center

Disclosure: Nothing to disclose.

Paul Krusinski, MD, Director of Dermatology, Fletcher Allen Health Care; Professor, Department of Internal Medicine, University of Vermont College of Medicine

Disclosure: Nothing to disclose.

Pranatharthi Haran Chandrasekar, MBBS, MD, Professor, Department of Internal Medicine, Director of Infectious Disease Fellowship, Harper Hospital, Wayne State University School of Medicine

Disclosure: Nothing to disclose.

Richard H Sinert, DO, Professor of Emergency Medicine, Clinical Assistant Professor of Medicine, Research Director, State University of New York College of Medicine; Consulting Staff, Department of Emergency Medicine, Kings County Hospital Center

Disclosure: Nothing to disclose.

Richard P Vinson, MD, Assistant Clinical Professor, Department of Dermatology, Texas Tech University Health Sciences Center, Paul L Foster School of Medicine; Consulting Staff, Mountain View Dermatology, PA

Disclosure: Nothing to disclose.

Timothy McCalmont, MD, Director, UCSF Dermatopathology Service, Professor of Clinical Pathology and Dermatology, Departments of Pathology and Dermatology, University of California at San Francisco; Editor-in-Chief, Journal of Cutaneous Pathology

Disclosure: Apsara Consulting fee Independent contractor

Specialty Editors

Daniel R Lucey, MD, MPH, Chief, Fellowship Program Director, Department of Internal Medicine, Division of Infectious Diseases, Washington Hospital Center; Professor, Department of Internal Medicine, Uniformed Services University of the Health Sciences

Disclosure: Nothing to disclose.

Francisco Talavera, PharmD, PhD, Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Medscape Salary Employment

John L Brusch, MD, FACP, Assistant Professor of Medicine, Harvard Medical School; Consulting Staff, Department of Medicine and Infectious Disease Service, Cambridge Health Alliance

Disclosure: Nothing to disclose.

Dirk M Elston, MD, Director, Ackerman Academy of Dermatopathology, New York

Disclosure: Nothing to disclose.

Chief Editor

Michael Stuart Bronze, MD, David Ross Boyd Professor and Chairman, Department of Medicine, Stewart G Wolf Endowed Chair in Internal Medicine, Department of Medicine, University of Oklahoma Health Science Center

Disclosure: Nothing to disclose.

References

  1. Cox DL, Chang P, McDowall AW, Radolf JD. The outer membrane, not a coat of host proteins, limits antigenicity of virulent Treponema pallidum. Infect Immun. Mar 1992;60(3):1076-83. [View Abstract]
  2. Fitzgerald TJ. The Th1/Th2-like switch in syphilitic infection: is it detrimental?. Infect Immun. Sep 1992;60(9):3475-9. [View Abstract]
  3. CDC. Primary and secondary syphilis--United States, 2003-2004. MMWR Morb Mortal Wkly Rep. Mar 17 2006;55(10):269-73. [View Abstract]
  4. Centers for Disease Control and Prevention. Sexually Transmitted Disease Surveillance 2007 Supplement, Syphilis Surveillance Report. Centers for Disease Control and Prevention. Centers for Disease Control and Prevention. Available at http://www.cdc.gov/std/Syphilis2007/. Accessed April 14.
  5. World Health Organization. Global prevalence and incidence of selected curable sexually transmitted infections: Overview and estimates. Geneva: 2001;
  6. Akovbian VA, Gomberg MA, Prokhorenkov VI. Syphilitic vignettes from Russia. Dermatol Clin. Oct 1998;16(4):687-90, x. [View Abstract]
  7. Centers for Disease Control and Prevention. Sexually Transmitted Disease Surveillance, 2007. 33 2008.;Atlanta, Georgia:
  8. CDC. Trends - STD Surveillance 2006. Department of Health and Human Services. Available at http://www.cdc.gov/std/stats/trends2006.htm#syphilistrends
  9. CDC. Summary of notifiable diseases, United States, 1997. MMWR Morb Mortal Wkly Rep. Nov 20 1998;46(54):ii-vii, 3-87. [View Abstract]
  10. Nakashima AK, Rolfs RT, Flock ML, Kilmarx P, Greenspan JR. Epidemiology of syphilis in the United States, 1941--1993. Sex Transm Dis. Jan-Feb 1996;23(1):16-23. [View Abstract]
  11. Centers for Disease Control and Prevention. STD Surveillance 2003, Atlanta, Ga. 2004.;Centers for Disease Control and Prevention.
  12. HARRISON LW. The Oslo study of untreated syphilis, review and commentary. Br J Vener Dis. Jun 1956;32(2):70-8. [View Abstract]
  13. ROCKWELL DH, YOBS AR, MOORE MB Jr. THE TUSKEGEE STUDY OF UNTREATED SYPHILIS; THE 30TH YEAR OF OBSERVATION. Arch Intern Med. Dec 1964;114:792-8. [View Abstract]
  14. McClure EM, Goldenberg RL. Infection and stillbirth. Semin Fetal Neonatal Med. Aug 2009;14(4):182-9. [View Abstract]
  15. Kupka R, Kassaye T, Saathoff E, Hertzmark E, Msamanga GI, Fawzi WW. Predictors of stillbirth among HIV-infected Tanzanian women. Acta Obstet Gynecol Scand. 2009;88(5):584-92. [View Abstract]
  16. Dismukes WE, Delgado DG, Mallernee SV, Myers TC. Destructive bone disease in early syphilis. JAMA. Dec 6 1976;236(23):2646-8. [View Abstract]
  17. Sule RR, Deshpande SG, Dharmadhikari NJ, Joshi VR. Late cutaneous syphilis. Cutis. Mar 1997;59(3):135-7. [View Abstract]
  18. [Guideline] Workowski KA, Berman S. Sexually transmitted diseases treatment guidelines, 2010. MMWR Recomm Rep. Dec 17 2010;59:1-110. [View Abstract]
  19. [Guideline] U.S. Preventive Services Task Force. Screening for Syphilis Infection. Recommendation Statement. 2004.
  20. [Guideline] Workowski KA, Berman SM. Sexually transmitted diseases treatment guidelines, 2006. MMWR Recomm Rep. Aug 4 2006;55:1-94. [View Abstract]
  21. Schmid GP. Serologic screening for syphilis. Rationale, cost, and realpolitik. Sex Transm Dis. Jan-Feb 1996;23(1):45-50. [View Abstract]
  22. Young H. Syphilis. Serology. Dermatol Clin. Oct 1998;16(4):691-8. [View Abstract]
  23. Binnicker MJ, Jespersen DJ, Rollins LO. Direct comparison of the traditional and reverse syphilis screening algorithms in a population with a low prevalence of syphilis. J Clin Microbiol. Jan 2012;50(1):148-50. [View Abstract]
  24. U.S. Preventive Services Task Force. Screening for syphilis infection in pregnancy: U.S. Preventive Services Task Force reaffirmation recommendation statement. Ann Intern Med. May 19 2009;150(10):705-9. [View Abstract]
  25. CDC. Penicillin Allergy-STD Treatment Guidelines 2006. Department of Health and Human Services. Available at http://www.cdc.gov/std/treatment/2006/penicillin-allergy.htm
  26. Fiumara NJ. Treatment of primary and secondary syphilis. Serological response. JAMA. Jun 27 1980;243(24):2500-2. [View Abstract]
  27. Augenbraun M, Workowski K. Ceftriaxone therapy for syphilis: report from the emerging infections network. Clin Infect Dis. Nov 1999;29(5):1337-8. [View Abstract]
  28. Bai ZG, Yang KH, Liu YL, Tian JH, Ma B, Mi DH, et al. Azithromycin vs. benzathine penicillin G for early syphilis: a meta-analysis of randomized clinical trials. Int J STD AIDS. Apr 2008;19(4):217-21. [View Abstract]
  29. [Best Evidence] Hook EW 3rd, Behets F, Van Damme K, Ravelomanana N, Leone P, Sena AC, et al. A phase III equivalence trial of azithromycin versus benzathine penicillin for treatment of early syphilis. J Infect Dis. Jun 1 2010;201(11):1729-35. [View Abstract]
  30. Centers for Disease Control and Prevention (CDC). Azithromycin treatment failures in syphilis infections--San Francisco, California, 2002-2003. MMWR Morb Mortal Wkly Rep. Mar 12 2004;53(9):197-8. [View Abstract]
  31. Golden MR, Wasserheit JN. Prevention of viral sexually transmitted infections--foreskin at the forefront. N Engl J Med. Mar 26 2009;360(13):1349-51. [View Abstract]
  32. Tobian AA, Serwadda D, Quinn TC, Kigozi G, Gravitt PE, Laeyendecker O, et al. Male circumcision for the prevention of HSV-2 and HPV infections and syphilis. N Engl J Med. Mar 26 2009;360(13):1298-309. [View Abstract]
  33. Augenbraun MH, Rolfs R. Treatment of syphilis, 1998: nonpregnant adults. Clin Infect Dis. Jan 1999;28 Suppl 1:S21-8. [View Abstract]

Syphilis. These photographs depict the characteristic chancre observed in primary syphilis. Used with permission from Wisdom A. Color Atlas of Sexually Transmitted Diseases. Year Book Medical Publishers Inc; 1989.

Syphilitic chancre

Syphilis. This photograph depicts primary syphilis "kissing" lesions. Used with permission from Wisdom A. Color Atlas of Sexually Transmitted Diseases. Year Book Medical Publishers Inc; 1989.

Syphilis. These photographs show the disseminated rash observed in secondary syphilis. Used with permission from Wisdom A. Color Atlas of Sexually Transmitted Diseases. Year Book Medical Publishers Inc; 1989.

Secondary syphilis - Exanthem

empty para to satisfy content model

Syphilis. Palmar lesions observed in secondary syphilis. Used with permission from Wisdom A. Color Atlas of Sexually Transmitted Diseases. Year Book Medical Publishers Inc; 1989.

These photographs illustrate examples of condylomata lata. The lesions resemble genital warts (condylomata acuminata). Fluids exuding from these lesions are highly infectious. Used with permission from Wisdom A. Color Atlas of Sexually Transmitted Diseases. Year Book Medical Publishers Inc; 1989.

Condylomata lata

Syphilis. These photographs show close-up images of gummas observed in tertiary syphilis. Used with permission from Wisdom A. Color Atlas of Sexually Transmitted Diseases. Year Book Medical Publishers Inc; 1989.

Syphilis. This photograph illustrates chorioretinitis of congenital syphilis. Used with permission from Wisdom A. Color Atlas of Sexually Transmitted Diseases. Year Book Medical Publishers Inc; 1989.

Syphilis. This photograph shows an example of Hutchinson teeth in congenital syphilis. Note notching. Used with permission from Wisdom A. Color Atlas of Sexually Transmitted Diseases. Year Book Medical Publishers Inc; 1989.

Syphilis. This is a dark-field micrograph of spirochetes. Used with permission from Murray P et al. Medical Microbiology. 2nd ed. Mosby; 1994.

Lues hematoxylin and eosin stain. Histopathological examination shows a lichenoid infiltrate that is stereotypical of the secondary stage of syphilis. Note that vacuolar alteration of the superjacent epithelium can be seen much like a noninfectious form of lichenoid dermatitis. The subjunctional infiltrate is rich in histiocytes and plasmacytes. At times, an overtly granulomatous lichenoid infiltrate can be seen.

Lues TP stain. Immunoperoxidase staining for T pallidum highlights many slender coiled organisms residing in the perijunctional zone. Occasionally, organisms can also be found in the upper dermis or around adnexal structures.

Syphilis. These photographs depict the characteristic chancre observed in primary syphilis. Used with permission from Wisdom A. Color Atlas of Sexually Transmitted Diseases. Year Book Medical Publishers Inc; 1989.

Syphilis. These photographs show the disseminated rash observed in secondary syphilis. Used with permission from Wisdom A. Color Atlas of Sexually Transmitted Diseases. Year Book Medical Publishers Inc; 1989.

Syphilis. These photographs show close-up images of gummas observed in tertiary syphilis. Used with permission from Wisdom A. Color Atlas of Sexually Transmitted Diseases. Year Book Medical Publishers Inc; 1989.

Syphilis. This is a dark-field micrograph of spirochetes. Used with permission from Murray P et al. Medical Microbiology. 2nd ed. Mosby; 1994.

Syphilis. This photograph depicts primary syphilis "kissing" lesions. Used with permission from Wisdom A. Color Atlas of Sexually Transmitted Diseases. Year Book Medical Publishers Inc; 1989.

Syphilis. Palmar lesions observed in secondary syphilis. Used with permission from Wisdom A. Color Atlas of Sexually Transmitted Diseases. Year Book Medical Publishers Inc; 1989.

These photographs illustrate examples of condylomata lata. The lesions resemble genital warts (condylomata acuminata). Fluids exuding from these lesions are highly infectious. Used with permission from Wisdom A. Color Atlas of Sexually Transmitted Diseases. Year Book Medical Publishers Inc; 1989.

Syphilis. These photographs illustrate typical facies of congenital syphilis. Used with permission from Wisdom A. Color Atlas of Sexually Transmitted Diseases. Year Book Medical Publishers Inc; 1989.

Syphilis. This photograph shows an example of Hutchinson teeth in congenital syphilis. Note notching. Used with permission from Wisdom A. Color Atlas of Sexually Transmitted Diseases. Year Book Medical Publishers Inc; 1989.

Syphilis. This photograph illustrates chorioretinitis of congenital syphilis. Used with permission from Wisdom A. Color Atlas of Sexually Transmitted Diseases. Year Book Medical Publishers Inc; 1989.

Syphilitic chancre

Secondary syphilis - Exanthem

empty para to satisfy content model

Condylomata lata

Lues hematoxylin and eosin stain. Histopathological examination shows a lichenoid infiltrate that is stereotypical of the secondary stage of syphilis. Note that vacuolar alteration of the superjacent epithelium can be seen much like a noninfectious form of lichenoid dermatitis. The subjunctional infiltrate is rich in histiocytes and plasmacytes. At times, an overtly granulomatous lichenoid infiltrate can be seen.

Lues TP stain. Immunoperoxidase staining for T pallidum highlights many slender coiled organisms residing in the perijunctional zone. Occasionally, organisms can also be found in the upper dermis or around adnexal structures.