You are in: eMedicine Specialties > Dermatology > FUNGAL INFECTIONS FavusArticle Last Updated: Feb 26, 2007AUTHOR AND EDITOR INFORMATIONSection 1 of 11
  Author: Jacek C Szepietowski, MD, PhD, Professor and Vice-Head, Department of Dermatology, Venereology and Allergology, Wroclaw Medical University, Poland Coauthor(s): Robert A Schwartz, MD, MPH, Professor and Head of Dermatology, Professor of Medicine, Professor of Pediatrics, Professor of Pathology, Professor of Preventive Medicine and Community Health, UMDNJ-New Jersey Medical School Editors: Franklin Flowers, MD, Chief, Division of Dermatology, Professor, Department of Medicine and Otolaryngology, University of Florida College of Medicine; Richard P Vinson, MD, Assistant Clinical Professor, Department of Dermatology, Texas Tech University School of Medicine; Consulting Staff, Mountain View Dermatology, PA; Paul Krusinski, MD, Director of Dermatology, Professor, Department of Internal Medicine, Fletcher Allen Health Care, University of Vermont; Catherine Quirk, MD, Clinical Assistant Professor, Department of Dermatology, Brown University; William D James, MD, Paul R Gross Professor of Dermatology, University of Pennsylvania School of Medicine; Vice-Chair, Program Director, Department of Dermatology, University of Pennsylvania Health System Author and Editor Disclosure Synonyms and related keywords: tinea favosa, favus honeycomb ringworm, tinea favosa capitis INTRODUCTIONSection 2 of 11
  BackgroundFavus, also termed tinea favosa, is a chronic inflammatory dermatophytic infection usually caused by Trichophyton schoenleinii. Rarely, favus is caused by Trichophyton violaceum, Trichophyton mentagrophytes var quinckeanum, or Microsporum gypseum. Favus typically affects scalp hair but also may infect glabrous skin and nails. The causative agent of mouse favus is T mentagrophytes var quinckeanum, also termed Trichophyton quinckeanum, which can cause favus in humans, although rarely. PathophysiologyFavus is a superficial dermatophyte infection usually caused by T schoenleinii. In most patients, favus is a severe form of tinea capitis; however, it may occur, although rarely, as onychomycosis, tinea barbae, or tinea corporis. Favus is 1 of 3 primary patterns of hair infection (ectothrix, endothrix, favus). Typically, hair is not as heavily infected as in trichophytosis caused by Trichophyton tonsurans. Hair is able to grow, and frequently, long hairs are observed in the disease state. The most characteristic feature is the formation of air spaces between hyphae within the infected hair. These air spaces (air tunnels) form as a result of autolysis of the hyphae. Arthroconidia rarely are seen within the hair. Such infected hair commonly is termed favus-type hair. In the sera of patients, antibodies to causative fungi are found by charcoal agglutination and immunodiffusion assay; however, the exact role of antibodies is not clear. FrequencyUnited StatesFavus is uncommon in the United States, although foci have been described in past decades in rural areas of West Virginia, New York, Kentucky, and Arkansas. Favus often is seen in geographic regions where lifestyles are associated with malnutrition, neglect, and poverty. InternationalFoci have been seen worldwide, including Poland, Southern and Northern Africa, Pakistan, the United Kingdom, Australia, South America (Brazil), and the Middle East. Mortality/MorbidityPermanent alopecia with scarring often follows favus, which is a chronic disfiguring infection. RaceFavus shows no racial or ethnic preference. SexBoth females and males may be affected equally; however, some report a slight predominance of female patients with favus. AgeFavus appears in both children and adults. Favus usually is acquired during childhood or adolescence and typically persists into adulthood. CLINICALSection 3 of 11
HistoryFavus usually begins on the scalp, often in childhood, and persists for many years as unsightly, crusted plaques. According to the severity of the disease, 3 main stages are described.
PhysicalThe scutulum, a yellow cup-shaped crust that surrounds a hair and pierces its center, is characteristic. Scutula form a dense plaque, each composed of mycelia and epidermal debris. Often, a secondary bacterial infection occurs in the plaque. Plaque removal leaves an erythematous moist base. The dense masses of yellow crusts may be solitary or numerous, and in patients who are severely affected, involve the entire scalp. A mousy odor typically is present. Glabrous skin may show similar yellow crusting. On glabrous skin, favus is a papulovesicular and papulosquamous eruption in which typical scutula may be evident. As an onychomycosis, tinea favosa resembles other forms of tinea unguium. In addition to typical scutular favus on the scalp, several atypical manifestations of favus have been described.
CausesPrimarily caused by T schoenleinii, favus rarely may be caused by T violaceum, T mentagrophytes var quinckeanum, or M gypseum. Although vertical transmission may occur, family attack rates are highly variable. Most evidence suggests that favus is not a highly contagious disease. DIFFERENTIALSSection 4 of 11
Candidiasis, Cutaneous Folliculitis Lupus Erythematosus, Discoid Pseudopelade, Brocq Psoriasis, Plaque Seborrheic Dermatitis Tinea Capitis
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| Drug Name | Griseofulvin (Fulvicin P/G, Grifulvin V) |
|---|---|
| Description | Fungistatic activity. Dermatophytes are sensitive, but yeastlike fungi and molds are resistant. Fungal cell division is impaired by interfering with microtubule. Binds to keratin precursor cells. Keratin is gradually replaced by noninfected tissue, which is highly resistant to fungal invasions. |
| Adult Dose | 500 mg microsize (330-375 mg ultramicrosize) PO divided bid |
| Pediatric Dose | 20-25 mg microsize/kg/d PO divided bid or 15 mg ultramicrosize/kg/d PO divided bid |
| Contraindications | Documented hypersensitivity; hepatic injury |
| Interactions | Reduced effects of cyclosporine, salicylates, and warfarin (decreased hypoprothrombinemic activity); contraceptives may lose their effectiveness; avoid alcohol use (disulfiramlike reaction may occur); intense UV light exposure may cause phototoxic reaction |
| Pregnancy | C - Safety for use during pregnancy has not been established. |
| Precautions | On prolonged therapy, observe patients closely; monitor renal, hepatic, and hematopoietic function regularly; Lupus-like syndromes or exacerbation of lupus erythematosus may occur; photosensitivity may also occur and thus patients should take protective measures against exposure to ultraviolet light or sunlight; take with or just after fatty food (increases absorption); reported adverse effects most commonly include abdominal pain, nausea, diarrhea, and headache |
| Drug Name | Terbinafine (Lamisil) |
|---|---|
| Description | Fungicidal agent and member of allylamine family. Inhibits squalene epoxidase, which decreases ergosterol synthesis, causing fungal-cell death. Use until symptoms significantly improve. In young children, tab may be split and hidden in food. |
| Adult Dose | 250 mg/d PO for minimum of 4 wk; not to exceed 12 wk |
| Pediatric Dose | <2 years (usually <12 kg): Not established <20 kg: 62.5 mg/d PO single dose 21-40 kg: 125 mg/d PO single dose >40 kg: 250 mg/d PO single dose |
| Contraindications | Documented hypersensitivity |
| Interactions | May decrease cyclosporine effects; toxicity of terbinafine may increase with rifampin and cimetidine |
| Pregnancy | B - Usually safe but benefits must outweigh the risks. |
| Precautions | Discontinue use if chemical irritation develops with topical use or if hepatobiliary dysfunction, neutropenia, or Stevens-Johnson syndrome develops; changes in the ocular lens and retina reported; in controlled trials; clinical significance of this unknown; generally well tolerated but approximately 10.5% of patients show adverse effects, primarily GI; transient loss of sense of taste is rare but specific adverse effect |
| Drug Name | Itraconazole (Sporanox) |
|---|---|
| Description | Fungistatic activity. Synthetic triazole antifungal agent that slows fungal cell growth by inhibiting cytochrome P-450-dependent synthesis of ergosterol, a vital component of fungal cell membranes. Not registered for administration in children in most countries. |
| Adult Dose | 400 mg/d PO divided bid for 1 wk or 200 mg/d PO divided bid for 4 wk |
| Pediatric Dose | <20 kg: 3-5 mg/kg/d PO divided bid >20 kg: 100 PO single dose or 200 mg/d PO divided bid |
| Contraindications | Coadministration of terfenadine, astemizole, or cisapride with Sporanox (itraconazole cap); concomitant administration with oral triazolam or with oral midazolam; administration for the treatment of onychomycosis to pregnant patients or to women contemplating pregnancy |
| Interactions | Frequent: Increased level of cyclosporine, tacrolimus, and digoxin may occur after coadministration; phenytoin and rifampin may decrease itraconazole effect; amlodipine and nifedipine taken with itraconazole may cause edema; hypoglycemia was observed after coadministration with sulfonylureas; avoid alcohol use, since disulfiramlike reactions may occur; antacids may reduce absorption; coadministration with terfenadine (recalled from US market), astemizole (recalled from US market), lovastatin, simvastatin, cisapride, triazolam, and midazolam; serious cardiovascular events, including death, were reported in patients treated with itraconazole and H1-receptor inhibitors (terfenadine, astemizole); coadministration with cisapride may cause arrhythmia; coadministration with triazolam and midazolam may increase their plasma levels; rhabdomyolysis may occur with coadministration of HMG-CoA reductase inhibitors (lovastatin, simvastatin) |
| Pregnancy | C - Safety for use during pregnancy has not been established. |
| Precautions | Caution in hepatic insufficiencies; generally well tolerated, but approximately 12% of patients show adverse effects, which primarily include GI abnormalities; hepatobiliary dysfunction was observed; take with fatty food, which increases absorption in alimentary tract |
| Drug Name | Fluconazole (Diflucan) |
|---|---|
| Description | Fungistatic activity. Synthetic oral antifungal (broad-spectrum bistriazole) that selectively inhibits fungal cytochrome P-450 and sterol C-14 alpha-demethylation, which prevents conversion of lanosterol to ergosterol, thereby disrupting cellular membranes. |
| Adult Dose | 150 mg PO qwk for approximately 6 wk |
| Pediatric Dose | <6 months: Not established >6 months: 5-6 mg/kg/d PO for 4-6 wk (liquid or tab) |
| Contraindications | Documented hypersensitivity |
| Interactions | Levels may increase with thiazides; fluconazole levels may decrease with chronic coadministration of rifampin; coadministration of fluconazole may decrease phenytoin clearance; may increase concentrations of theophylline, tolbutamide, glyburide, and glipizide; effects of anticoagulants may increase with fluconazole coadministration; increases in cyclosporine concentrations may occur when administered concurrently |
| Pregnancy | C - Safety for use during pregnancy has not been established. |
| Precautions | Adjust dose in renal insufficiency; monitor closely if rashes develop and discontinue drug if lesions progress; may cause clinical hepatitis, cholestasis and fulminant hepatic failure (including death), with underlying medical conditions such as AIDS or a malignancy and while taking multiple concomitant medications; not recommended for breastfeeding; convenience and efficacy of single dose regimen for treatment of vaginal yeast infections should be weighed against difficulties resulting from higher incidence of adverse reactions reported with oral fluconazole versus intravaginal agents; generally well tolerated, but approximately 12% of patients show adverse effects, which primarily include nausea, vomiting, abdominal discomfort, and hepatotoxicity |
| Media file 1: Tinea favosa of the scalp shows erythematous lesions with pityroid scaling. Some hairs are short and brittle. | |
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| Media file 2: Favus of the scalp shows extensive lesions with scarring alopecia. | |
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| Media file 3: Typical fluorescence under Wood lamp examination. | |
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| Media file 4: Favus, wax montage. Courtesy of Professor Dr Feliks Wasik, Dermatology, Medical University of Wroclaw, Poland. | |
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| Media file 5: Black man, aged 45 years, with favuslike yellow crusting of scalp. Potassium hydroxide and fungal culture were negative. | |
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| Media file 6: Culture of Trichophyton schoenleinii on Sabouraud agar. Courtesy of Anna Pawlowicz, PhD, and Professor Barbara Raszeja-Kotelba, MD, Dermatology, University School of Poznan, Poland. | |
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| Media file 7: Culture of Trichophyton schoenleinii on Sabouraud agar. Note pleomorphism of the culture. Courtesy of Anna Pawlowicz, PhD, and Professor Barbara Raszeja-Kotelba, MD, Dermatology, University School of Poznan, Poland. | |
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| Media file 8: Microculture of Trichophyton schoenleinii shows dichotomic branching and terminal swelling. Light-field microscopy, original magnification X 1000. Courtesy of Anna Pawlowicz, PhD, and Professor Barbara Raszeja-Kotelba, MD, Dermatology, University School of Poznan, Poland. | |
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| Media file 9: Microculture of Trichophyton schoenleinii shows characteristic dichotomic branching. Light-field microscopy, original magnification X 1000. Courtesy of Anna Pawlowicz, PhD, and Professor Barbara Raszeja-Kotelba, MD, Dermatology, University School of Poznan, Poland. | |
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| Media file 10: Microculture of Trichophyton schoenleinii shows numerous terminal chlamydospores. Light-field microscopy, original magnification X 1200. Courtesy of Anna Pawlowicz, PhD, and Professor Barbara Raszeja-Kotelba, MD, Dermatology, University School of Poznan, Poland. | |
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| Media file 11: Infected hair filled with hyphae shows bubbles of gas and gas tunnels (light field microscopy, original magnification X 2300). | |
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Article Last Updated: Feb 26, 2007
