THE MERCK MANUAL: The Merck Manual of Diagnosis and Therapy
Print Topic

Sections

Chapters

Tinea Versicolor

-
-

Tinea versicolor is skin infection with Malassezia furfur that manifests as multiple asymptomatic scaly patches varying in color from white to tan to brown to pink. Diagnosis is based on clinical appearance and potassium hydroxide wet mount of skin scrapings. Treatment is with topical or sometimes oral antifungals. Recurrence is common.

Malassezia furfur is a dimorphic fungus that is normally a harmless component of normal skin flora but that in some people causes tinea versicolor. Most affected people are healthy. Factors that may predispose to tinea versicolor include heat and humidity and immunosuppression due to corticosteroids, pregnancy, undernutrition, diabetes, or other disorders. Hypopigmentation in tinea versicolor is due to the inhibition of tyrosinase caused by M. furfur production of azelaic acid.

Tinea versicolor usually is asymptomatic. Classically, it causes the appearance of multiple tan, brown, salmon, pink, or white scaling patches on the trunk, neck, abdomen, and occasionally face. The lesions may coalesce. In light-skinned patients, the condition is often diagnosed in summer months because the lesions, which do not tan, become more obvious against tanned skin. Tinea versicolor is benign and is not considered contagious.

  • Clinical appearance
  • Potassium hydroxide wet mount
  • Sometimes Wood light examination

Diagnosis is based on clinical appearance and by identification of hyphae and budding cells (“spaghetti and meatballs”) on potassium hydroxide wet mount of fine scale scrapings. A Wood light examination reveals golden-white fluorescence.

  • Topical antifungals
  • Sometimes oral antifungals

Treatment is any topical antifungal drug. Examples include selenium sulfide shampoo 2.5% (in 10-min applications daily for 1 wk or 24-h applications weekly for 1 mo); topical azoles (eg, ketoconazole 2% daily for 2 wk); and daily bathing with zinc pyrithione soap 2% or sulfur-salicylic shampoo 2% for 1 to 2 wk.

Oral treatment is indicated for patients with extensive disease and those with frequent recurrences. Two convenient regimens are a single 400-mg dose of ketoconazole or fluconazole 150 mg/wk for 2 to 4 wk.

Hypopigmentation from tinea versicolor is reversible in months to years after the yeast has cleared.

Recurrence is almost universal after treatment because the causative organism is a normal skin inhabitant. Fastidious hygiene, regular use of zinc pyrithione soap, or once-monthly use of topical antifungal therapy lowers the likelihood of recurrence.

  • Although tinea versicolor can occur in immunosuppressed patients, most affected patients are healthy.
  • The disorder is frequently diagnosed in the summer, but mainly because hypopigmented lesions become more obvious against tanned skin.
  • Try to confirm the diagnosis by finding hyphae and budding cells on potassium hydroxide wet mount of fine scale scrapings.
  • Treat with topical or oral antifungals.

Last full review/revision March 2013 by Denise M Aaron, MD

Copyright     © 2010-2013 Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc., Whitehouse Station, N.J., U.S.A.    Privacy    Terms of Use