Viral Pharyngitis



Viral pharyngitis can be caused by numerous viruses. Acute pharyngitis is an inflammatory syndrome of the pharynx and/or tonsils caused by several different groups of microorganisms. Pharyngitis can be part of a generalized upper respiratory tract infection or a specific infection localized in the pharynx.

Most cases are caused by viruses and occur as part of common colds and influenzal syndromes. For information on bacterial pharyngitis, see the article Bacterial Pharyngitis in the Infectious Diseases volume.


Several viruses can cause viral pharyngitis.


More than 100 different serotypes of rhinovirus cause approximately 20% of cases of pharyngitis and 30-50% of common colds. These viruses enter the body through the ciliated epithelium that lines the nose, causing edema and hyperemia of the nasal mucous membranes. This condition leads to increased secretory activity of the mucous glands; swelling of the mucous membranes of the nasal cavity, eustachian tubes, and pharynx; and narrowing of nasal passages, causing obstructive symptoms. Bradykinin and lysyl-bradykinin are generated in the nasal passages of patients with rhinovirus colds, and these mediators stimulate pain nerve endings. The virus does not invade the pharyngeal mucosa. Transmission occurs by large particle aerosols or fomites.


In children, adenovirus causes uncomplicated pharyngitis (most commonly caused by adenovirus types 1-3 and 5) or pharyngoconjunctival fever. The latter is characterized by fever, sore throat, and conjunctivitis. Unlike rhinovirus infections, adenovirus directly invades the pharyngeal mucosa, as shown by the viral cytopathic effect.

Epstein-Barr virus

Epstein-Barr virus (EBV) is the causal agent of infectious mononucleosis. EBV usually spreads from adults to infants. Among young adults, EBV spreads through saliva and, rarely, through blood transfusion. In addition to edema and hyperemia of the tonsils and pharyngeal mucosa, an inflammatory exudate and nasopharyngeal lymphoid hyperplasia also develop. Pharyngitis or tonsillitis is present in about 82% of patients with infectious mononucleosis.

Herpes simplex virus

Herpes simplex virus (HSV) types 1 and 2 cause gingivitis, stomatitis, and pharyngitis. Acute herpetic pharyngitis is the most common manifestation of the first episode of HSV-1 infection. After HSV enters the mucosal surface, it initiates replication and infects either sensory or autonomic nerve endings. The neurocapsid of the virus is intra-axonally transported to the nerve cell bodies in the ganglia and contiguous nerve tissue. The virus then spreads to other mucosal surfaces through centrifugal migration of infectious virions via peripheral autonomic or sensory nerves. This mode of spread explains the high frequency of new lesions distant from the initial crop of vesicles characteristic of oral-labial HSV infection.

Influenza virus

Pharyngitis and sore throat develop in about 50% of the patients with influenza A and in a lesser proportion of patients with influenza B. Severe pharyngitis is particularly common in patients with type A. The influenza virus invades the respiratory epithelium, causing necrosis, which predisposes the patient to secondary bacterial infection. Transmission of influenza occurs by aerosolized droplets.

Parainfluenza virus

Pharyngitis caused by parainfluenza virus types 1-4 usually manifests as the common cold syndrome. Parainfluenza virus type 1 infection occurs in epidemics, mainly in late fall or winter, while parainfluenza virus type 2 infection occurs sporadically. Parainfluenza virus type 3 infection occurs either epidemically or sporadically.


Pharyngitis caused by coronavirus usually manifests as the common cold. As in rhinovirus colds, viral mucosal invasion of the respiratory tract does not occur.


The major groups of enteroviruses that can cause pharyngitis are coxsackievirus and echovirus. Although enteroviruses are primarily transmitted by the fecal-oral route, airborne transmission is important for certain serotypes. Enteroviral lesions in the oropharyngeal mucosa are usually a result of secondary infection of endothelial cells of small mucosal vessels, which occurs during viremia following enteroviral infection in the GI tract.

Respiratory syncytial virus

Transmission of respiratory syncytial virus (RSV) occurs by fomites or large-particle aerosols produced by coughing or sneezing. The pathogenesis of RSV infection remains unclear, although a number of theories exist. Immunologic mechanisms may contribute to the pathogenesis of the severe disease in infants and elderly patients.


Acute acquired cytomegalovirus (CMV) infection is transmitted by sexual contact, in breast milk, via respiratory droplets among nursery or day care attendants, and by blood transfusion. Infection in the immunocompetent host rarely results in clinically apparent disease. Infrequently, immunocompetent hosts exhibit a mononucleosislike syndrome with mild pharyngitis.

Human immunodeficiency virus

Pharyngitis develops in patients infected with human immunodeficiency virus (HIV) as part of the acute retroviral syndrome, a mononucleosislike syndrome that is the initial manifestation of HIV infection in one half to two thirds of recently infected individuals.



United States

Each year, pharyngitis is responsible for more than 40 million visits to health care providers. Most children and adults experience 3-5 viral upper respiratory tract infections (including pharyngitis) per year.


Worldwide, acute infections of the respiratory tract are one of the main causes of disease, and most of these are due to viruses.


Worldwide, viral pharyngitis is one of the most common causes of absence from school or work. The National Ambulatory Medical Care Survey showed that upper respiratory tract infections, including acute pharyngitis, accounted for 200 annual visits to a physician per 1000 population between 1980-1996. The vast majority of upper respiratory tract infections are due to viruses.


Viral pharyngitis affects all races and ethnic groups equally.


Viral pharyngitis affects both sexes equally.


Viral pharyngitis affects both children and adults, but it is more common in children. For more information on pediatric pharyngitis, see Pediatric Pharyngitis.


Sore throat is the chief symptom in patients with viral pharyngitis. Patients may have additional symptoms that vary based on the causal pathogen. These symptoms are generally not useful in discriminating between the causes of viral pharyngitis because the symptoms produced by the numerous viruses that cause pharyngitis are so similar and commonly overlap each other.

Pharyngitis in the common cold syndrome

Sore throat is usually not the primary symptom. Nasal symptoms, such as sneezing, watery nasal discharge, nasal congestion, or postnasal discharge, tend to precede throat symptoms. Throat symptoms can be in the form of soreness, scratchiness, or irritation. Nasal discharge may be thick and yellow. Nonproductive cough may be present. Fever, if present, is usually low grade and is more prominent in young children than in adults. Hoarseness is sometimes present. Severe pharyngeal pain or odynophagia is unusual. Chills, myalgia, and profound malaise are usually not prominent.

Pharyngitis caused by adenovirus

Pharyngitis caused by adenovirus is common among young children and military recruits. Patients with pharyngitis present with sore throat (more intense than that of a common cold), high fever, dysphagia, and red eyes. Red eyes are due to concurrent conjunctivitis, which occurs in one third to one half of affected patients, along with fever. This syndrome is named pharyngoconjunctival fever. The patient may have a history of swimming pool exposure approximately 1 week before the onset of illness. Military personnel tend to be more ill with hoarseness, chest pain, and respiratory distress.

Pharyngitis associated with EBV infectious mononucleosis

EBV infectious mononucleosis is most commonly observed in adolescents and young adults. Sore throat and fatigue are the most common symptoms. Pharyngeal symptoms are usually associated with other features of the disease (eg, fatigue, skin rash, anorexia).

Acute herpetic pharyngitis

Acute herpetic pharyngitis is most commonly observed in children and young adults. Sore throat may be accompanied by sore mouth with associated gingivostomatitis. Other symptoms include fever, myalgia, malaise, inability to eat, and irritability.

Pharyngitis with influenza

Sore throat is the chief symptom in some patients with influenza. The onset of illness is usually abrupt, with myalgia, headache, fever, chills, and dry cough. The pharyngitis usually resolves in 3-4 days. Cases generally occur in an epidemic pattern, usually in late fall or winter in North America.

Pharyngitis caused by enteroviruses

Enteroviruses are an important cause of viral pharyngitis in childhood. This condition has a peak occurrence in late summer and early fall. Distinctive clinical syndromes include (1) herpangina caused by coxsackievirus A2-6; (2) acute lymphonodular pharyngitis caused by coxsackievirus A10; (3) hand-foot-and-mouth disease caused by coxsackievirus A5, 9, 10, and 16, and enterovirus 71; and (4) Boston exanthem caused by echovirus type 16.

Young children with herpangina have sore throat, sore mouth, and severe odynophagia. Sudden onset of fever (temperature of up to 106°F/41°C), coryza, and anorexia are common presenting symptoms. Twenty-five percent of children vomit. Older children develop neck pain, headache, and back pain. Herpangina is not associated with gingivitis, in contrast to acute herpetic pharyngitis.

Children with hand-foot-and-mouth disease have low-grade grade fever (temperature, 100-102°F/38-39°C), sore throat, sore mouth, anorexia, malaise, and rash on the hands and feet.

Children with Boston exanthem have sudden onset of fever, sore throat, nausea, and rash over the face and trunk.

Pharyngitis caused by RSV

Immunocompetent adults with RSV infection present with nasal discharge, sore throat, low-grade fever, and cough. Infants, elderly persons, and patients with chronic obstructive pulmonary disease (COPD) or congestive heart failure are more likely to develop lower respiratory tract involvement, which manifests as dyspnea, wheezing, and respiratory failure. Outbreaks of illness occur during the fall, winter, and early spring.

Pharyngitis caused by CMV

Patients who have CMV infection tend to be older than those with EBV infectious mononucleosis. Sore throat is less salient, but fever and malaise are prolonged and are more prominent than in EBV infectious mononucleosis.

Pharyngitis caused by HIV

Patients with primary HIV infection (acute retroviral syndrome) develop acute sore throat similar to infectious mononucleosis. Sore throat is usually accompanied by other symptoms. Fever, sweats, malaise, lethargy, myalgias, anorexia, nausea, diarrhea, and skin rash are prominent symptoms.


Edema and erythema of the pharynx are typical in viral pharyngitis. The degree of erythema does not correlate with the degree of soreness. Exudate can be present but is generally less effusive than in bacterial pharyngitis.

Pharyngitis in the common cold syndrome

Redness around the external nares from nose blowing may be noted. Nasal mucosa is often erythematous. Mild erythema of the pharynx is usually present.

Pharyngitis caused by adenovirus

Examination of the oropharynx reveals pharyngeal erythema with exudates. When associated with conjunctivitis, both bulbar and palpebral conjunctivae are involved without purulent discharge. The palpebral conjunctivae usually have a granular appearance. Although the onset is frequently monocular, the other eye usually becomes involved. Conjunctivitis often persists after fever and other symptoms have resolved. Preauricular and cervical lymphadenopathy may be present.

Pharyngitis associated with infectious mononucleosis

Examination of the oral cavity and pharynx reveals the characteristic marked enlargement of the tonsils. Half of patients with infectious mononucleosis have a coating of thick, continuous exudates, mimicking streptococcal pharyngitis. The uvula may also be swollen. Unilateral palatal swelling and tenderness may be present.

Palatal petechiae may be observed in both infectious mononucleosis and streptococcal pharyngitis. However, palatal petechiae associated with infectious mononucleosis tend to be confined to the soft palate. Fever may reach a temperature of up to 104°F/40°C. Periorbital edema is common.

Tender lymphadenopathy is most prominent in the posterior and anterior cervical regions, but axillary and inguinal nodes may also be enlarged. Splenomegaly is present in 50% of patients; hepatomegaly in approximately 10-15%; jaundice in 5%; and a fine, variable form rash in about 5%. More than 90% of patients given ampicillin develop a diffuse, pruritic maculopapular eruption.

Acute herpetic pharyngitis

Examination of the oral cavity and pharynx shows characteristic painful shallow ulcers with red margins or vesicles on the hard and soft palates, posterior pharynx, and tonsillar pillars. Exudates may be present on the lesions. These lesions can be present on the tongue, gingiva, lips, or buccal mucosa with an associated gingivostomatitis. Lesions on the tongue, gingiva, or buccal mucosa may appear late in the course in one third of cases. Fever and tender cervical lymphadenopathy are common. Fever may reach temperatures of up to 106°F/41°C in children younger than 5 years. Clinically differentiating acute herpetic pharyngitis from bacterial pharyngitis can be difficult.

Pharyngitis with influenza

Edema and erythema of pharyngeal mucosa may be present but usually to a mild degree. Pharyngeal or tonsillar exudates and cervical lymphadenopathy are absent. Fever with temperatures of up to 104°F/40°C is common. Profound fatigue and conjunctival injection are usually prominent.

Enteroviral pharyngitis

Herpangina is characterized by multiple small vesicles (1-2 mm) on the tonsils, tonsillar pillars, uvula, or soft palate. Vesicles may enlarge to 4 mm or have an erythematous ring as large as 10 mm. Vesicles become shallow ulcers in about 3 days and then heal. The remainder of the pharynx is usually normal.

Boston exanthem is characterized by pharyngeal erythema and a roseolalike salmon-pink maculopapular rash over the face and trunk.

Pharyngitis caused by CMV

Physical findings in CMV mononucleosis syndrome are similar to those in EBV infectious mononucleosis except for less prominent pharyngeal signs. The pharynx may be mildly erythematous or almost normal in appearance. Splenomegaly is less common and prominent than in EBV infectious mononucleosis.

Pharyngitis caused by HIV

Examination of the oral cavity and pharynx reveals tonsillar hypertrophy without exudate. Cervical, occipital, or axillary lymphadenopathy is a frequent manifestation; hepatosplenomegaly is less common. Oral aphthous ulcerations have been reported in several cases. A rash that may be maculopapular, roseolalike, or urticarial develops in 40-80% of patients.


Rhinovirus and adenovirus are the most common etiological agents, and each accounts for 6-20% of all cases of pharyngitis, both viral and nonviral.

Less common etiological agents include EBV, HSV, influenza virus, parainfluenza virus, and coronavirus.

Uncommon etiological agents include enterovirus (eg, poliovirus, coxsackievirus, echovirus), RSV, CMV, rotavirus, reovirus, rubella virus, varicella-zoster virus, measles virus, and HIV-1.

Laboratory Studies

The similarity of signs and symptoms of viral pharyngitis make a specific etiological diagnosis virtually impossible without various laboratory tests. In many circumstances, etiological diagnosis is of no practical use because it may not alter the treatment and prognosis. Viral cultures are not needed to diagnose pharyngitis other than in a research setting.

The total WBC count may initially be slightly elevated without bandemia, followed by a decrease to fewer than 5000 cells/µL after 4-7 days of illness in about 50% of cases.

Atypical lymphocytosis is frequently associated with EBV and CMV infections.

Results from a rapid streptococcal antigen test and a bacterial culture of throat swab in viral pharyngitis may be positive (approximately 30% of patients with EBV infectious mononucleosis are colonized with group A streptococci).

Common cold

Specific virological diagnosis is unnecessary for practical purposes because it may not alter the management. Cultures of nasal secretions, serological tests, and polymerase chain reaction (PCR) techniques can be used for specific virological diagnosis. Rapid viral antigen detection tests are not sensitive enough to be useful.

EBV infectious mononucleosis

After week one of illness, peripheral blood film reveals relative and absolute lymphocytosis, with more than 10% atypical lymphocytes. Hemolytic anemia and thrombocytopenia secondary to anti-i antibodies are occasionally observed. Erythrocyte sedimentation rate (ESR) is elevated and liver function test results are mildly abnormal in about 90% of cases. Heterophile agglutination test (immunoglobulin M [IgM] antibody) results are positive with a titer of 40-fold or greater in 90% of affected adolescents and adults within the first few weeks after the onset of infectious mononucleosis symptoms. A mononucleosis spot test (Monospot) allows rapid screening for heterophile antibodies. Heterophile test results are usually negative in children younger than 4 years. Positive results for IgM antibody to viral capsid antigen and positive results for antibody to early antigen are useful to diagnose acute infection, particularly in cases that are heterophile negative.


Leukopenia and proteinuria are nonspecific findings in influenza. Virus isolation or detection of viral antigen in respiratory secretions is very useful to diagnose acute illness. Virus can be readily isolated from nasal swab specimens, throat swab specimens, nasal washes, or combined nose-and-throat swab specimens by inoculation of embryonated eggs or cell cultures. Rapid detection of viral antigen directly in respiratory secretions can be accomplished by immunofluorescent (IF) studies, time-resolved immunofluorescence assay (TRFIA), radioenzyme immunoassay, and enzyme-linked immunosorbent assay (ELISA).

PCR techniques have been described for rapid detection of influenza virus RNA in clinical samples. Serological tests can be used, but they are not helpful for diagnosis and treatment of acute disease secondary to delay in obtaining the antibody titers in convalescent sera. Serological tests are useful for epidemiological purposes. A rise in complement-fixing and hemagglutination-inhibiting antibody levels during the second week is considered diagnostic of acute infection.

Enterovirus infection

Positive results on an enteroviral-specific reverse transcriptase-polymerase chain reaction (RT-PCR) test of throat swabs are diagnostic. Etiological diagnosis is not necessary for clinical purposes because it may not alter treatment.

RSV infection

RSV antigen in nasal secretions can be reliably detected with commercially available rapid tests.

CMV infection

A relative lymphocytosis is characteristic of acute CMV pharyngitis. Atypical lymphocytes may represent 10% or more of the total. CMV can be readily isolated from a throat swab. Positive results on the CMV-specific IgM antibody titers are diagnostic of acute infection. Results of heterophile tests are usually negative (heterophile-negative mononucleosis syndrome). A 4-fold or greater rise in antibody titers is confirmatory but useful only for epidemiological purposes.

Acute retroviral syndrome (primary HIV infection)

Serological test results for HIV are usually negative during the phase of acute retroviral syndrome because the test takes approximately 4 weeks for seroconversion. HIV RNA assay by PCR technique and p24 antigen assay can be used to help confirm the diagnosis. HIV viral load is usually extremely high. The peripheral blood picture may resemble infectious mononucleosis. Heterophile test results are usually negative (heterophile-negative mononucleosis syndrome).

Medical Care

Treatment strategies for patients with acute pharyngitis are based on epidemiologic factors, signs and symptoms, and results of laboratory tests.[1] Rest, oral fluids, and salt-water gargling (for soothing effect) are the main supportive measures in patients with viral pharyngitis.[2]

Analgesics and antipyretics may be used for relief of pain or pyrexia. Acetaminophen is the drug of choice. Traditionally, aspirin has been used, but it may increase viral shedding. Aspirin should not be used in children or adolescents, especially with influenza, because of its association with Reye syndrome. One study proved that ibuprofen was superior to acetaminophen for symptomatic relief in children aged 6-12 years. A double-blind randomized study involving adult patients from 27 study centers in Latin America found that 5 days of treatment with celecoxib 200 mg once daily is as effective as diclofenac 75 mg twice daily in the symptomatic treatment of viral pharyngitis.[3]

Anesthetic gargles and lozenges, such as benzocaine, may be used for symptomatic relief. Hospitalization for intravenous hydration may be necessary when odynophagia is intense.

Antibiotics do not hasten recovery or reduce the frequency of bacterial complications. The risks of prescribing antibiotics in patients with viral pharyngitis include the common side effects of antibiotics (diarrhea, rashes, candidiasis, unplanned pregnancy secondary to oral-contraceptive failure) and the rare occurrence of anaphylaxis.[4]

Specific treatment of viral infections is available for only a few viruses.


Amantadine and rimantadine are FDA approved for treatment of influenza A virus infections among adults and children aged 1 year or older. However, because of resistance in circulating influenza A virus strains, they are no longer recommended for antiviral treatment of influenza A.[5] Adamantanes, particularly amantadine, can be associated with a significant discontinuation rate due to CNS side effects such as lightheadedness, difficulty concentrating, nervousness, and insomnia in older adults.[6]

The Advisory Committee on Immunization Practices (ACIP) recommends antiviral treatment with a neuraminidase inhibitor (oseltamivir or zanamivir) for outpatients with suspected or confirmed influenza who are at higher risk for influenza complications because of age or underlying medical conditions. Persons at higher risk for influenza complications recommended for antiviral treatment include the following:[5]

The greatest benefit is when antiviral treatment is started within 48 hours of influenza illness onset. Antiviral treatment also can be considered for any previously healthy, symptomatic outpatient not at high risk with confirmed or suspected influenza on the basis of clinical judgment, if treatment can be initiated within 48 hours of illness onset.

A 2014 systematic review published in the Cochrane Library found that neuraminidase inhibitors have small nonspecific effects on reducing the time to alleviation of influenza symptoms in healthy adults, but not in asthmatic children.[7] Treatment trials with oseltamivir or zanamivir do not settle the question of whether the complications of influenza (eg, pneumonia) are reduced because of a lack of diagnostic definitions. The use of oseltamivir increases the risk of adverse effects such as nausea, vomiting, psychiatric effects, and renal events in adults and vomiting in children. The Cochrane authors concluded that the balance between benefits and harms should be considered when making decisions about neuraminidase inhibitors for treatment of influenza and that the influenza virus–specific mechanism of action proposed by the producers does not fit the clinical evidence.

Updated information about influenza activity and antiviral resistance can be found on the Web sites of the US Centers for Disease Control and Prevention[8] and the World Health Organization.[9]

EBV infectious mononucleosis

Specific antiviral therapy with acyclovir, ganciclovir, and interferon alfa reduces viral shedding but does not improve clinical outcome.

Corticosteroids may improve the symptoms, but they are generally not recommended because infectious mononucleosis is usually benign and self-limited.

However, corticosteroids are indicated if the patient has massive tonsillar hypertrophy that threatens to obstruct the airway.

Herpes simplex virus

In an immunocompetent host, oral acyclovir, famciclovir, and valacyclovir decrease the duration of symptoms and viral shedding.

In an immunocompromised host, these drugs decrease pain and viral shedding and accelerate healing of lesions. These drugs are helpful in severely afflicted patients.

Acute retroviral syndrome

Several unique considerations favor antiretroviral therapy during this phase of HIV infection. Treatment may limit the extent of viral dissemination throughout the body, attenuate the progress of HIV infection by lowering the plasma viral RNA set point, and limit the extent of viral genetic variability, which is responsible for drug resistance.

Treatment may also allow salvage of a CD4 T-cell–specific immune response that may be important in the immune control of HIV infection.


Drinking large amounts of fluid is recommended. No specific dietary restrictions are needed. Soft, cold foods (eg, ice cream, popsicles) are more easily tolerated.


No restriction in activity is required.

Medication Summary

The goal of pharmacotherapy is primarily to reduce morbidity. Analgesics/antipyretics and topical anesthetics are mainstay of pharmacological treatment. Most of these agents have been available for many years and are available without prescription.

A recent prospective, randomized, double-blind, placebo-controlled, multicenter study[10] showed that patients with viral pharyngitis who received chlorhexidine gluconate/benzydamine hydrochloride mouth spray reported less pain on both day 3 and day 7. Further, recipients of chlorhexidine/benzydamine reported a significantly better quality of life on day 7. Chlorhexidine/benzydamine was well tolerated, and no serious adverse events were observed during this trial.

Acetaminophen (Tylenol)

Clinical Context:  Relieves pain by elevation of the pain threshold. Reduces fever by acting directly on hypothalamic heat-regulating centers, which increases dissipation of body heat via vasodilation and sweating.

Ibuprofen (Advil, Motrin)

Clinical Context:  Inhibits inflammatory reactions and pain by decreasing prostaglandin synthesis.

Class Summary

These agents are often helpful in relieving the pain and fever associated with pharyngitis.

Benzocaine (Trocaine, Benzocol, Cylex, Cepacol Maximum Strength)

Clinical Context:  Lozenges or gargle reduces pain associated with pharyngitis. Inhibits neuronal membrane depolarization, blocking nerve impulses.

Class Summary

These agents soothe irritated or inflamed mucous membranes associated with sore throat.

Amantadine (Symmetrel)

Clinical Context:  Active against influenza A virus. Has little or no activity against influenza B virus isolates. Mechanism of antiviral action is unclear. Prevents release of infectious viral nucleic acid into the host cell by interfering with the function of the transmembrane domain of the viral M2 protein. In certain cases, known to prevent virus assembly during virus replication. Treatment begun within 48 h of the onset of symptoms decreases the duration of fever and other symptoms.

Rimantadine (Flumadine)

Clinical Context:  Inhibits viral replication of influenza A virus H1N1, H2N2, and H3N2 with little or no activity against influenza B virus. Prevents penetration of the virus into the host by inhibiting uncoating of influenza A. Does not appear to interfere with the immunogenicity of inactivated influenza A vaccine. Can be used together during an outbreak.

Oseltamivir (Tamiflu)

Clinical Context:  Inhibits neuraminidase, which is a glycoprotein on the surface of influenza virus that destroys an infected cell's receptor for viral hemagglutinin. By inhibiting viral neuraminidase, decreases release of viruses from infected cells and thus viral spread. Effective to treat influenza A or B. Start within 40 h of symptom onset. Available as capsules and an oral suspension.

Acyclovir (Zovirax)

Clinical Context:  Synthetic purine nucleoside analogue with in vitro and in vivo inhibitory activity against HSV-1, HSV-2, and VSV. Inhibitory activity is highly selective because of its affinity for the enzyme thymidine kinase (TK) encoded by HSV and VZV.

Valacyclovir (Valtrex)

Clinical Context:  Prodrug rapidly converted to the active drug acyclovir. More expensive but has a more convenient dosing regimen than acyclovir.

Famciclovir (Famvir)

Clinical Context:  Prodrug that when biotransformed into active metabolite, penciclovir, may inhibit viral DNA synthesis/replication.

Class Summary

These agents are used specifically to treat viral infections. They are available for only a few viruses.

Zanamivir (Relenza)

Clinical Context:  Inhibitor of neuraminidase, which is a glycoprotein on the surface of the influenza virus that destroys the infected cell's receptor for viral hemagglutinin. By inhibiting viral neuraminidase, release of viruses from infected cells and viral spread are decreased. Effective against both influenza A and B. To be inhaled through Diskhaler oral inhalation device. Circular foil discs containing 5-mg blisters of drug are inserted into supplied inhalation device.


Washing hands frequently, using disposable tissues, and limiting human contact are important preventive measures for the common cold syndrome and other viral pharyngitis. No consistent benefit was demonstrated in preventing a common cold with large doses of vitamin C.

Live adenovirus vaccines have been successfully used in military populations but are not available for civilian use.

Administration of influenza vaccine to high-risk individuals and those who want to prevent influenza is the major preventive measure. Amantadine may be used to prevent influenza A during outbreaks.


The complication rate of viral pharyngitis associated with a common cold is quite low. Purulent bacterial otitis media and sinusitis may occur.

Infectious mononucleosis may be complicated by tonsillar and peritonsillar abscess, necrotic epiglottitis, airway obstruction, hepatic dysfunction, splenic rupture, hypersplenism, encephalitis, pneumonitis, pericarditis, and hematologic disorders.

Herpetic pharyngitis may lead to necrotizing tonsillitis, epiglottitis, and recurrent disease.

Influenza may be complicated by secondary bacterial pneumonia. Pneumococcal pneumonia is most common. Staphylococcal pneumonia is most serious.

RSV infection, particularly in infants, elderly persons, and patients with underlying COPD, may be complicated by pneumonia and respiratory failure.

Complications of HIV infection are beyond the scope of this article. For more information, see the article HIV Disease.


The prognosis of a patient with a common cold is excellent. Most adults recover in less than a week, and most children in less than 2 weeks.

In patients with infectious mononucleosis, fever disappears in approximately 10 days. Lymphadenopathy and splenomegaly disappear in approximately 4 weeks. Debility sometimes remains for approximately 2-3 months, and the condition is occasionally fatal because of splenic rupture, hypersplenism, or encephalitis.

The duration of uncomplicated influenza is 1-7 days. Prognosis is excellent. Most fatalities are due to secondary bacterial pneumonia.

Enteroviral pharyngitis is usually benign and self-limited.

Patient Education

Patient education should emphasize the natural course of viral infection and that it takes several days to feel better. Patients must understand that antibiotics are not needed for sore throats of viral origin. Risk of allergic reactions, fungal superinfection, and bacterial resistance should be discussed.

Patients should be reassured that certain measures, including pain relievers, throat sprays or lozenges, and gargling with warm salt water, improve symptoms without antibiotics. It is often challenging to reassure that antibiotic therapy is unnecessary.[2]

Fever persisting for more than 5 days, extreme throat pain causing dysphagia, inability to open the mouth wide, or fainting spells when standing should prompt a visit to a doctor.

For excellent patient education resources, visit eMedicineHealth's Cold and Flu Center, Infections Center, and Ear, Nose, and Throat Center. Also, see eMedicineHealth's patient education articles Colds, Sore Throat, Mononucleosis, and Tonsillitis.


KoKo Aung, MD, MPH, FACP, Professor of Internal Medicine, Associate Academic Dean, Assistant Vice President, Texas Tech University Health Sciences Center, Paul L Foster School of Medicine

Disclosure: Nothing to disclose.


Ambrish Ojha, MBBS,

Disclosure: Nothing to disclose.

Carson Lo, MD, Consultant, West Houston Infectious Disease Associates

Disclosure: Nothing to disclose.

Specialty Editors

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

Disclosure: Received salary from Medscape for employment. for: Medscape.

Gordon L Woods, MD, Consulting Staff, Department of Internal Medicine, University Medical Center

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; Master of the American College of Physicians; Fellow, Infectious Diseases Society of America

Disclosure: Nothing to disclose.

Additional Contributors

Gregory William Rutecki, MD, Professor of Medicine, Fellow of The Center for Bioethics and Human Dignity, University of South Alabama College of Medicine

Disclosure: Nothing to disclose.


  1. Perkins A. An approach to diagnosing the acute sore throat. Am Fam Physician. 1997 Jan. 55(1):131-8, 141-2. [View Abstract]
  2. Bisno AL. Acute pharyngitis. N Engl J Med. 2001 Jan 18. 344(3):205-11. [View Abstract]
  3. Weckx LL, Ruiz JE, Duperly J, et al. Efficacy of celecoxib in treating symptoms of viral pharyngitis: a double-blind, randomized study of celecoxib versus diclofenac. J Int Med Res. 2002 Mar-Apr. 30(2):185-94. [View Abstract]
  4. Graham A, Fahey T. Evidence based case report. Sore throat: diagnostic and therapeutic dilemmas. BMJ. 1999 Jul 17. 319(7203):173-4. [View Abstract]
  5. Fiore AE, Fry A, Shay D, Gubareva L, Bresee JS, Uyeki TM. Antiviral agents for the treatment and chemoprophylaxis of influenza --- recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR Recomm Rep. 2011 Jan 21. 60(1):1-24. [View Abstract]
  6. Keyser LA, Karl M, Nafziger AN, Bertino JS Jr. Comparison of central nervous system adverse effects of amantadine and rimantadine used as sequential prophylaxis of influenza A in elderly nursing home patients. Arch Intern Med. 2000 May 22. 160(10):1485-8. [View Abstract]
  7. Jefferson T, Jones MA, Doshi P, Del Mar CB, Hama R, Thompson MJ, et al. Neuraminidase inhibitors for preventing and treating influenza in healthy adults and children. Cochrane Database Syst Rev. 2014 Apr 10. 4:CD008965. [View Abstract]
  8. CDC. Seansonal Flu Weekly Report. Available at Accessed: July 29, 2011.
  9. WHO. Infleunza Update. Available at Accessed: July 29, 2011.
  10. Cingi C, Songu M, Ural A, Yildirim M, Erdogmus N, Bal C. Effects of chlorhexidine/benzydamine mouth spray on pain and quality of life in acute viral pharyngitis: a prospective, randomized, double-blind, placebo-controlled, multicenter study. Ear Nose Throat J. 2010 Nov. 89(11):546-9. [View Abstract]
  11. Ebell MH, Smith MA, Barry HC, et al. The rational clinical examination. Does this patient have strep throat?. JAMA. 2000 Dec 13. 284(22):2912-8. [View Abstract]
  12. Little P, Gould C, Williamson I, Warner G, Gantley M, Kinmonth AL. Reattendance and complications in a randomised trial of prescribing strategies for sore throat: the medicalising effect of prescribing antibiotics. BMJ. 1997 Aug 9. 315(7104):350-2. [View Abstract]
  13. McIsaac WJ, White D, Tannenbaum D, et al. A clinical score to reduce unnecessary antibiotic use in patients with sore throat. CMAJ. 1998 Jan 13. 158(1):75-83. [View Abstract]
  14. Singh S, Dolan JG, Centor RM. Optimal management of adults with pharyngitis--a multi-criteria decision analysis. BMC Med Inform Decis Mak. 2006 Mar 13. 6:14. [View Abstract]
  15. Cunha BA. Group A streptococcal pharyngitis. Emerg Med. 1990. 22:93-96.
  16. Cunha BA. Group A streptococcal pharyngitis versus colonization. Intern Med. 1994. 15:18-19.
  17. Cunha BA. The Sore Throat: Mycoplasma pneumoniae pharyngitis. Emerg Med. 1988. 20:245-252.
  18. Gwaltney JM Jr, Bisno AL. Pharyngitis. Mandell GI, Bennett JE, Dolin R, eds. Mandell, Douglas & Bennett's Principles of Infectious Diseases. Churchill Livingstone; 2000. Vol 1: 656-62.
  19. Huovinen P, Lahtonen R, Ziegler T, et al. Pharyngitis in adults: the presence and coexistence of viruses and bacterial organisms. Ann Intern Med. 1989 Apr 15. 110(8):612-6. [View Abstract]
  20. McIsaac WJ, Goel V, Slaughter PM. Reconsidering sore throats. Part 2: Alternative approach and practical office tool. Can Fam Physician. 1997 Mar. 43:495-500. [View Abstract]
  21. McIsaac WJ, Goel V, Slaughter PM, et al. Reconsidering sore throats. Part I: Problems with current clinical practice. Can Fam Physician. 1997 Mar. 43:485-93. [View Abstract]
  22. Paradise JL. Etiology and management of pharyngitis and pharyngotonsillitis in children: a current review. Ann Otol Rhinol Laryngol Suppl. 1992 Jan. 155:51-7. [View Abstract]
  23. Pichichero ME. Sore throat after sore throat after sore throat. Are you asking the critical questions?. Postgrad Med. 1997 Jan. 101(1):205-6, 209-12, 215-8, passim. [View Abstract]
  24. Wolter JM. Management of a sore throat. Antibiotics are no longer appropriate. Aust Fam Physician. 1998 Apr. 27(4):279-81. [View Abstract]
  25. Yoda K, Sata T, Kurata T, et al. Oropharyngotonsillitis associated with nonprimary Epstein-Barr virus infection. Arch Otolaryngol Head Neck Surg. 2000 Feb. 126(2):185-93. [View Abstract]