Paronychia

Practice Essentials

Paronychia is a soft tissue infection around a fingernail that begins as cellulitis but that may progress to a definite abscess.^[1] The 2 types of paronychia are as follows^[2] :

• Acute paronychia - Painful and purulent condition; most frequently caused by staphylococci
• Chronic paronychia - Usually caused by a fungal infection

The image below depicts paronychia.

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Classic presentation of paronychia, with erythema and pus surrounding the nail bed. In this case, the paronychia was due to infection after a hangnail....

Signs and symptoms

Physical findings in acute paronychia include the following:

• The affected area often appears erythematous and swollen
• In more advanced cases, pus may collect under the skin of the lateral fold
• If untreated, the infection can extend into the eponychium, in which case it is called eponychia

Further extension of the infection can lead to the involvement of both lateral folds as it tracks under the nail sulcus; this progression is called a runaround infection

Physical findings in chronic paronychia include the following:

• Swollen, erythematous, and tender nail folds without fluctuance are characteristic of chronic paronychia
• Eventually, the nail plates become thickened and discolored, with pronounced transverse ridges
• The cuticles and nail folds may separate from the nail plate, forming a space for the invasion of various microorganisms

See Clinical Presentation for more detail.

Diagnosis

The diagnosis of paronychia is based primarily on patient history and physical examination. Some laboratory studies, however, can be useful. These include the following:

• Gram staining and/or culture - To help identify a bacterial cause of fluctuant paronychia
• Potassium hydroxide (KOH) 5% smears - To help diagnose paronychia caused by a candidal infection
• Tzanck smears - If herpetic whitlow is suspected
• See Workup for more detail.

Management

Treatment strategies for paronychia include the following:

• If soft tissue swelling is present without fluctuance, the infection may resolve with warm soaks 3-4 times daily^{[1, 3, 4]}
• Patients with extensive surrounding cellulitis or with a history of diabetes, peripheral vascular disease, or an immunocompromised state may benefit from a short course of antibiotics^{[5, 6]}
• If an abscess has developed, incision and drainage must be performed

See Treatment and Medication for more detail.

• References

Background

Paronychia is a soft tissue infection around a fingernail. More specifically, it is a superficial infection of epithelium lateral to the nail plate that begins as cellulitis but that may progress to a definite abscess.^[1] The 2 forms of paronychia, acute and chronic, usually differ in etiology, infectious agent, and treatment and are often considered separate entities.^[2]

The acute infection, which is painful and purulent, is most frequently caused by staphylococci, although it commonly has mixed aerobic and anaerobic flora.^[7] The patient's condition and discomfort are markedly improved by a simple drainage procedure. Chronic paronychial infections are usually fungal, rather than bacterial, in nature (see the images below).

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Classic presentation of paronychia, with erythema and pus surrounding the nail bed. In this case, the paronychia was due to infection after a hangnail....

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In this case of paronychia, no pus or fluctuance is involved in the nail bed itself.

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Typical appearance of paronychia.

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Epidemiology

Paronychia is the most common hand infection in the United States, representing 35% of these disorders.^[3] The infection is more common in women than in men, with a female-to-male ratio of 3:1.

Quality of life

A study by Belyayeva et al indicated that certain nail disorders, including paronychia, can have a particularly high impact on quality of life. Using responses to a questionnaire from 1063 patients with disorders of the fingernails and/or toenails, the investigators found that the effect on quality of life was greatest in patients with nail problems resulting from trauma, infections (including onychomycosis and paronychia), structural abnormalities, and inflammatory diseases (including psoriasis). Quality of life was particularly reduced in women, patients aged 60-79 years, and persons with multiple nail involvement.^[8]

According to the report, the results suggest that quality of life is influenced more by the effect of a nail disease on the appearance of the nail than it is by the actual severity of the disease.

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Anatomy

The nail organ is an integral component of the digital tip. It is a highly versatile tool that protects the fingertip, contributes to tactile sensation by acting as a counterforce to the fingertip pad, and aids in peripheral thermoregulation via glomus bodies in the nail bed and matrix. Because of its form and functionality, abnormalities of the nail unit result in functional and cosmetic issues.

The anatomy of the nail complex is shown in the image below. The nail is longitudinally flanked by 2 lateral folds, or perionychium. Proximally, it is covered by the eponychium. Distal to the perionychium, the region immediately beneath the free edge of the nail is the hyponychium. The hyponychium serves as a tough physical barrier that resists bacterial infection.

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Depicted are the nail fold (A), dorsal roof (B), ventral floor (C), nail wall (D), perionychium (E), lunula (F), nail bed (G), germinal matrix (H), st....

Nail plate and bed

The nail, or nail plate, lies immediately on top of the nail bed, which consists of the following 2 portions, which are involved in the production, migration, and maintenance of the nail:

• Proximal portion - Called the germinal matrix; contains active cells that are responsible for generating new nail; damage to the germinal matrix results in malformed nails
• Distal portion - Called the sterile matrix; adds thickness, bulk, and strength to the nail

The white, crescent-shaped opacity at the proximal end of the nail is the lunula, which is the visible portion of the germinal matrix. The whiteness of the lunula is due to the poor vascularity of the germinal matrix.

Nail fold

The nail arises from a mild proximal depression called the nail fold. The nail divides the nail fold into 2 components: the dorsal roof and the ventral floor, both of which contain germinal matrices. The skin overlying the nail fold is called the nail wall.

Vascular system

The nail bed receives its blood supply from the 2 terminal branches of the volar digital artery. A fine network in the proximal nail bed and in the skin proximal to the nail fold of the finger provides venous drainage. Lymphatic drainage follows a course similar to that of the venous network. The lymphatic network is dense in the nail bed, especially in the hyponychium. Innervation is derived from the trifurcation of the dorsal branch of the volar digital nerve. One branch goes to the nail fold, one to the pulp, and one to the distal tip of the finger.

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Pathophysiology and Etiology

Paronychia, whether acute or chronic, results from a breakdown of the protective barrier between the nail and the nail fold. The occurrence of cracks, fissures, or trauma allowing organisms to enter the moist nail crevice leads to bacterial or fungal (yeast or mold) colonization of the area.^[9] Early in the course of this disease process (< 24 h), cellulitis alone may be present. An abscess can form if the infection does not resolve quickly.

Acute paronychia

Acute paronychia usually results from a traumatic event, however minor, that breaks down the physical barrier between the nail bed and the nail; this disruption allows the infiltration of infectious organisms. (See the image below.)

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Paronychial erythema and edema with associated pustule. This suggests a bacterial etiology.

Acute paronychia can result from seemingly innocuous conditions, such as hangnails, or from activities such as nail biting, finger sucking, manicuring, or artificial nail placement. Causative organisms include the following^[10] :

• Staphylococcus aureus - The most common infecting organism
• Streptococcus species
• Pseudomonas species
• Gram-negative bacteria
• Anaerobic bacteria
• Fusarium species^[11]

Chronic paronychia

Chronic paronychia is caused primarily by the yeast fungus Candida albicans.^[12] Other, rare causes of chronic paronychia include the following:

• Bacterial, mycobacterial, or viral infection
• Metastatic cancer
• Subungual melanoma
• Squamous cell carcinoma
• Raynaud disease

Therefore, benign and malignant neoplasms should always be excluded when chronic paronychia does not respond to conventional treatment.

Chronic paronychia most often occurs in persons whose hands are repeatedly exposed to moist environments or in those who have prolonged and repeated contact with irritants such as mild acids, mild alkalis, or other chemicals. People who are most susceptible include housekeepers, dishwashers, bartenders, florists, bakers, and swimmers. In addition, individuals who are immunocompromised, such as those with human immunodeficiency virus (HIV) infection or those undergoing steroid therapy, are predisposed to paronychia.

Other conditions associated with abnormalities of the nail fold that predispose individuals to chronic paronychia include psoriasis, mucocutaneous candidiasis, and drug toxicity from medications such as retinoids, epidermal growth factor receptor inhibitors (cetuximab) (tyrosine kinase inhibitors [neratinib, afatinib]),^{[13, 14]} and protease inhibitors.^{[15, 16]} Of particular interest is the antiretroviral drug indinavir, which induces retinoidlike effects and remains the most frequent cause of chronic paronychia in patients with HIV disease.

Pemphigus vulgaris

Acute or chronic paronychia may also occur as a manifestation of other diseases, such as pemphigus vulgaris. Although nail involvement in pemphigus vulgaris is rare, it can be severe, involving multiple digits and hemorrhage.^[17]

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Prognosis

If treated promptly, paronychia usually has a good prognosis, but it potentially can result in a more serious infection, such as septic tenosynovitis, osteomyelitis,^[18] or, by spreading to the pulp space of the finger, a felon. Such infections develop more readily in patients who are immunosuppressed or in those whose condition has been mistreated or neglected. Secondary ridging, thickening, and discoloration of the nail can also occur, as may nail loss. Occasionally, patients suffer systemic infection from hematogenous extension.^[19]

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Patient Education

Instruct individuals to avoid any trauma to the fingernails and to avoid nail biting and finger sucking. Educate patients who work with their hands in a moist environment that such exposure predisposes them to infections. Inform patients that treatment is unlikely to be successful if their exposure to a moist or wet environment is not changed. Explain to patients who are immunocompromised that they must remain vigilant against any minor trauma to the fingertips and nails.

For patient education information, see the Skin Conditions and Beauty Center, as well as Paronychia (Nail Infection) and Nail Psoriasis.

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History

The patient's history is crucial in determining the possibility of systemic conditions and risk factors that may predispose an individual to paronychia.^{[15, 20, 21, 22, 23, 24]} These may include the following:

• Diabetes mellitus^[25]
• Obesity
• Hyperhidrosis
• Immunologic defects
• Polyendocrinopathy
• Drug-induced immunosuppression
• Retroviral use - Indinavir and lamivudine, in particular, are thought to be associated with an increased incidence of paronychia formation^{[26, 27]}

Patients may give a history of the following^{[9, 28]} :

• Nail biting
• Finger sucking
• Trivial finger trauma
• Finger exposure to chemical irritants
• Use of acrylic nails or nail glue
• Sculpted nails
• Frequent hand immersion in water

Also query patients about the duration of symptoms and a history of nail infections and previous treatment.

Because paronychia has been known to initiate from malignant lesions, any history of prior malignancy or a pigmented, irregular appearance of surrounding tissue should result in appropriate suspicion and referral for biopsy.

Painless swelling or severe swelling that radiates requires an expanded differential diagnosis.^[29] Painless swelling lateral to the nail plate in a patient with osteoarthritis should prompt investigation for a mucous cyst.

Acute paronychia

The patient is usually otherwise healthy but complains of pain, tenderness, and swelling in one of the lateral folds of the nail.

Chronic paronychia

Generally, patients report symptoms lasting 6 weeks or longer. Inflammation, pain, and swelling may occur episodically, often after an exposure to water or a moist environment.

Chronic and recurrent paronychial infections should be scrutinized to rule out malignancy or fungal infection.^{[30, 31, 32]}

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Physical Examination

Acute paronychia

Physical findings in acute paronychia include the following:

• The affected area often appears erythematous and swollen
• In more advanced cases, pus may collect under the skin of the lateral fold
• If untreated, the infection can extend into the eponychium, in which case it is called eponychia
• Further extension of the infection can lead to the involvement of both lateral folds as it tracks under the nail sulcus; this progression is called a runaround infection

In severe cases, the infection may track proximally under the skin of the finger and volarly to produce a concomitant felon. The fulminant purulence of the nail bed may generate enough pressure to lift the nail off the nail bed.

Chronic paronychia

Physical findings in chronic paronychia include the following:

• Swollen, erythematous, and tender nail folds without fluctuance are characteristic of chronic paronychia
• Eventually, the nail plates become thickened and discolored, with pronounced transverse ridges
• The cuticles and nail folds may separate from the nail plate, forming a space for the invasion of various microorganisms

Additional considerations

Other signs to look for in a physical examination include the following:

• Look for signs of a herpetic whitlow, such as vesicles on an erythematous base
• Green coloration of the nail may suggest Pseudomonas species infection
• Hypertrophy of the nail plate may be a clue to fungal infection
• Constant severe pain with nail plate elevation, bluish discoloration of the nail plate, and blurring of the lunula suggest the presence of a glomus tumor.

The digital pressure test can be used to detect the presence of an abscess. Pressure is applied to the palmar surface of the distal finger; if an abscess is present, the area of the abscess will blanch with palmar pressure.^[33]

• References

Approach Considerations

The diagnosis of paronychia is based primarily on patient history and physical examination. Some laboratory studies, however, can be useful.

Fluctuant paronychia usually results from bacterial infection; therefore, routine Gram staining and culture can help in identifying the causative organism.

Potassium hydroxide (KOH) 5% smears may be helpful in diagnosing paronychia if Gram staining results are negative or if candidal infection is suspected, as in chronic paronychia. If Gram staining results are negative, the KOH preparation may demonstrate pseudomycelia and clusters of grapelike yeast cells. KOH wet mounts from scrapings or discharge may show hyphae.

Tzanck smears may be performed if herpetic whitlow is suspected. Smears should be performed by using base scrapings of an unroofed vesicle. The presence of multinucleated giant cells, often with visible viral inclusions, indicates a positive result.

Imaging studies

Although imaging studies are not routinely necessary with paronychia, obtain a plain film radiograph of the fingertip if osteomyelitis is suspected because of recurrent infection, elevated erythrocyte sedimentation rate (ESR), or presence of risk factors for osteomyelitis.

A radiograph can also be obtained if a foreign body is suspected or the patient has a history of recent finger trauma.

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Approach Considerations

The treatment of choice depends on the extent of the infection. If diagnosed early, acute paronychia without obvious abscess can be treated nonsurgically. If soft tissue swelling is present without fluctuance, the infection may resolve with warm soaks 3-4 times daily.^{[1, 3, 4]}

Patients with extensive surrounding cellulitis or with a history of diabetes, peripheral vascular disease, or an immunocompromised state may benefit from a short course of antibiotics. An antistaphylococcal penicillin or first-generation cephalosporin is generally effective; clindamycin and amoxicillin-clavulanate are also appropriate.^{[5, 6]}

If an abscess has developed, however, incision and drainage must be performed. Surgical debridement may be required if fulminant infection is present.^{[39, 40]}

Herpetic whitlow and paronychia must be distinguished because the treatments are drastically different. Misdiagnosis and mistreatment may do more harm than good. Once herpetic whitlow is ruled out, one must determine whether the paronychia is acute or chronic and then treat it accordingly.^[41]

Inpatient care

Admission for paronychia is rarely required unless associated with a significant cellulitis, tendonitis, or deep space infection of the hand requiring intravenous antibiotics.

Consultations

It is necessary to consult a hand surgeon if cellulitis, deep space infection, glomus tumor, mucous cyst, or osteomyelitis is suspected.

Long-term monitoring

Patients with recurring or chronic paronychia require frequent follow-up monitoring to prevent possible superinfections or deep-seated infections.

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Pharmacologic and Other Noninvasive Treatment

Acute paronychia

Warm water soaks of the affected finger 3-4 times per day until symptoms resolve are helpful.

Oral antibiotics with gram-positive coverage against S aureus, such as amoxicillin and clavulanic acid (Augmentin), clindamycin (Cleocin), or or cephalexin, are usually administered concomitantly with warm water soaks. (Although antibiotics are commonly prescribed,^[1] most patients do not require antibiotics for a simple paronychia.)

Cleocin and Augmentin also have anaerobic activity; therefore, they are useful in treating patients with paronychia due to oral anaerobes contracted through nail biting or finger sucking. Cleocin should be used instead of Augmentin in patients who are allergic to penicillin.

If the paronychia does not resolve or if it progresses to an abscess, it should be drained promptly.

Chronic paronychia

The initial treatment of chronic paronychia consists of the avoidance of inciting factors such as exposure to moist environments or skin irritants. Keeping the affected lesion dry is essential for proper recovery. Choice of footgear may also be considered.

Any manipulation of the nail, such as manicuring, finger sucking, or attempting to incise and drain the lesion, should be avoided; these manipulations may lead to secondary bacterial infections.

Mild cases of chronic paronychia may be treated with warm soaks, followed by completely drying the digit. The initial medical treatment consists of the application of topical antifungal agents. Topical miconazole may be used as the initial agent. Oral ketoconazole or fluconazole may be added in more severe cases.

Patients with diabetes and those who are immunocompromised need more aggressive treatment because the response to therapy is slower in these patients than in others.

In cases induced by retinoids or protease inhibitors, the paronychia usually resolves if the medication is discontinued.

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Drainage

If paronychia does not resolve despite best medical efforts, surgical intervention may be indicated. Also, if an abscess has developed, incision and drainage must be performed (see the image below). Surgical debridement may be required if fulminant infection is present.

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Paronychia incision and drainage.

Acute paronychia

No-incision technique

Less-advanced paronychial abscesses can be drained simply by gently elevating the eponychial fold from the nail by using a small blunt instrument such as a metal probe or an elevator (see the image below). This separation is performed at the junction of the perionychium and the eponychium and extends proximally enough to permit visualization of the proximal nail edge. Then, the proximal third of the nail can be excised with scissors and the pus evacuated.

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Simple acute paronychia can be drained by elevating the eponychial fold from the nail with a small blunt instrument such as a metal probe or elevator.....

This technique does not require an incision into the matrix. Often, no excision of any tissues is made, because only blunt dissection and separation are needed to evacuate the pus from the paronychia.

The wound should be well irrigated with isotonic sodium chloride solution, and plain gauze packing should be inserted under the fold to keep the cavity open and allow drainage.

The patient should receive oral antibiotics for 5-7 days. The packing is removed after 2 days, and warm sodium chloride solution soaks are begun.

Simple incision technique

The most simple and, often, least painful incision can be made without anesthesia, using only an 18-gauge needle. The technique is performed as follows:

• The needle is positioned bevel up and laid horizontally on the nail surface; it is inserted at the lateral nail fold where it meets the nail itself, at the point of maximum fluctuance
• The skin of the nail fold is lifted, releasing pus from the paronychia cavity
• A gentle side-to-side motion may then be used to increase the size of the incision made by the needle, improving drainage; since the area incised is made up mostly of necrotic tissue, this is often painless
• Gentle pressure can be placed on the external skin to express any remaining pus from the paronychia
• The cavity can then be irrigated with saline
• A small piece of 1/4-in gauze or iodoform tape can be inserted into the paronychia cavity for continued drainage. The wound is subsequently covered with a sterile bandage.

Single- and double-incision techniques

If the paronychia is more advanced, it may need to be incised and drained. A digital anesthetic block is usually necessary. If an anesthetic agent is used, it should consist of 1% lidocaine (Xylocaine).^{[4, 42]} The local injection of the anesthetic agent into the paronychia or the wound is often inadequate and more painful than the administration of drugs of a digital block.

If the paronychia involves only 1 lateral fold of the finger, a single longitudinal incision should be placed with either a number-11 or number-15 blade directed away from the nail fold to prevent proximal injury and a subsequent nail growth abnormality. If both lateral folds of the finger are involved, incisions may be made on both sides of the nail, extending proximally to the base of the nail.

The next steps are as follows (see the images below):

• After the single or double incision is made, the entire eponychial fold is elevated to expose the base of the nail and drain the pus
• The proximal third of the nail is removed by using the method described for the no-incision technique
• After the abscess is drained, the pocket should be well irrigated with isotonic sodium chloride solution, packed with plain packing, and dressed
• The patient should receive oral antibiotics for 5-7 days
• The dressing and packing are removed in approximately 2 days, and the affected finger is treated with warm soaks for 10-15 minutes 3-4 times per day

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  Wound opened with a small incision using a number-11 blade scalpel.

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  The wound can be explored with a blunt probe, clamps, or the blunt end of a cotton swab.

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  Ensure that all loculations are broken up and that as much pus as possible is evacuated.

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  Prior to packing or dressing the wound, irrigate the wound with normal saline under pressure, using a splash guard, eye protection, or both.

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  The wound can be covered with antibiotic ointment or petroleum jelly to prevent bandage adhesion.

   

  

   

Chronic paronychia

The most common surgical technique used to treat chronic paronychia is called eponychial marsupialization.

In this technique, the affected digit is first anesthetized with 1% lidocaine (Xylocaine), with no epinephrine, using the digital ring block method.

Tourniquet control of the proximal digit may be accomplished by using a finger of a latex glove with the distal end cut off or by using a sterile Penrose drain at the base of the digit firmly secured using a hemostat. The surgery proceeds as follows:

• With a No. 15 blade, a crescent-shaped incision is made proximal to the distal edge of the eponychial fold; the distal incision is made approximately 1 mm proximal to the distal edge of the eponychium and extends along its curve. A curvilinear proximal incision is then made, extending from the lateral ends of the distal incision and forming a crescent with its widest margin approximately 5 mm from the distal incision; the incision should appear symmetrical
• All affected tissue within the boundaries of the crescent and extending down to, but not including, the germinal matrix is excised
• In effect, this procedure exteriorizes the infected and obstructed nail matrix and allows its drainage
• If the nail plate is grossly deformed at the time of surgery, it may be removed
• The excised region is packed with plain gauze wick, which is changed every 2-3 days

Epithelialization of the excised defect occurs over the next 2-3 weeks. Nail improvement occurs over the next 6-9 months but may require as long as 12 months to become apparent.

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Prevention

Patients should also avoid any further trauma to or manipulation of the nail. Hangnails should be trimmed to a semilunar smooth edge with a clean, sharp nail plate trimmer. Toenails should be trimmed flush with the toe tip. Patients should not bite the nail plate or lateral nail folds.

Patients should also avoid prolonged hand exposure to moisture. (Rubber or latex-free gloves can be worn.) If hand washing must be frequent, patients should use antibacterial soap, thoroughly dry their hands with a clean towel, and apply an antibacterial moisturizer.

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Medication Summary

Most paronychia infections can be managed without antibiotics; over-the-counter analgesics are usually sufficient. If cellulitis is present, however, then antibiotics are indicated. Although penicillin covers oral flora, it does not cover methicillin-resistant Staphylococcus aureus (MRSA). Trimethoprim and sulfamethoxazole (TMP/SMZ), doxycycline, or clindamycin may be considered to cover community-acquired MRSA and anaerobic organisms. Cephalexin may also be effective. Combination therapy with an intravenous agent that provides antimicrobial activity against staphylococci is used for inpatient therapy.

Chronic paronychial infections are usually managed with oral antifungals such as ketoconazole, itraconazole, or fluconazole.^[43] Many of these agents require a prolonged course with monitoring of laboratory tests to avoid complications.

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Clindamycin (Cleocin)

• Dosing, Interactions, etc.

Clinical Context:  This agent is a lincosamide used in the treatment of serious skin and soft tissue staphylococcal infections. It is also effective against aerobic and anaerobic streptococci (except enterococci). Clindamycin inhibits bacterial growth, possibly by blocking the dissociation of peptidyl transfer ribonucleic acid (t-RNA) from ribosomes, causing RNA-dependent protein synthesis to arrest.

Clindamycin widely distributes in the body without penetration of the central nervous system (CNS). It is protein bound and excreted by the liver and kidneys.

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Amoxicillin and clavulanic acid (Augmentin, Augmentin XR, Amoclan)

• Dosing, Interactions, etc.

Clinical Context:  This drug combination is used against bacteria resistant to beta-lactam antibiotics. In children over age 3 months, base dosing protocol on amoxicillin content. Because the amoxicillin/clavulanic acid ratio in 250-mg tablets (250/125) is different than in 250-mg chewable tablets (250/62.5), do not use 250-mg tablets until the child weighs more than 40 kg.

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Penicillin VK

• Dosing, Interactions, etc.

Clinical Context:  Penicillin VK inhibits the biosynthesis of cell wall mucopeptide. It is bactericidal against sensitive organisms when adequate concentrations are reached. It is most effective during the stage of active multiplication. Inadequate concentrations may produce only bacteriostatic effects.

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Cephalexin (Keflex)

• Dosing, Interactions, etc.

Clinical Context:  This is a first-generation cephalosporin that arrests bacterial growth by inhibiting bacterial cell wall synthesis. It has bactericidal activity against rapidly growing organisms, with primary activity against skin flora. It is used for skin infections or for prophylaxis in minor procedures.

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Class Summary

Therapy must cover all likely pathogens in the context of this clinical setting.

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Miconazole topical (Desenex Spray, Lotrimin AF, Baza Antifungal, Carrington Antifungal, Micaderm, Micatin)

• Dosing, Interactions, etc.

Clinical Context:  This agent damages the fungal cell wall membrane by inhibiting the biosynthesis of ergosterol. By increasing membrane permeability, it causes nutrients to leak out of the cell, resulting in fungal cell death. Lotion is preferred in intertriginous areas. If cream is used, it should be applied sparingly to avoid maceration effects.

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Ketoconazole (Nizoral, Extina, Xologel)

• Dosing, Interactions, etc.

Clinical Context:  Ketoconazole has fungistatic activity. An imidazole with broad-spectrum antifungal action, it inhibits the synthesis of ergosterol, causing cellular components to leak and resulting in fungal cell death.

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Itraconazole (Sporanox, Onmel)

• Dosing, Interactions, etc.

Clinical Context:  This is a synthetic fungistatic triazole that inhibits cytochrome P-450–dependent synthesis of ergosterol, a vital component of fungal cell membranes.

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Class Summary

The mechanism of action of antifungal agents usually involves the alteration of the permeability of the cell membrane (polyenes) of the fungal cell or the inhibition of pathways (enzymes, substrates, transport) necessary for sterol/cell membrane synthesis.

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