« Back to Infections and Infestations

Superficial Fungal Infections

»	What is a dermatophyte?
»	How are superficial fungal infections diagnosed?
»	On a KOH examination, hyphal-like structures arranged in a mosaic pattern are noted. Does this indicate the presence of a dermatophyte?
»	What are the three most commonly used culture media for the growth of dermatophytes?
»	Describe some of the presentations of superficial fungal infections caused by dermatophytes.
»	Which dermatophyte causes the most fungal infections of skin?
»	What is the most common cause of tinea capitis in the United States?
»	Name the four clinical patterns of tinea capitis.
»	What are the types of hair invasion in tinea capitis? What dermatophytes are associated with each type?
»	What is a Wood’s light? What organisms are detected by this exam?
»	How is tinea capitis treated?
»	What is meant by a carrier state in tinea capitis?
»	Name the three types of tinea pedis. Which dermatophyte is most commonly associated with each?
»	What nondermatophyte mold can cause mycotic infections that mimic moccasin-type tinea pedis?
»	What is a dermatophytid reaction?
»	Name and describe the four clinical presentations of onychomycosis.
»	Can other diseases mimic onychomycosis?
»	What is tinea versicolor?
»	How does Malassezia induce both hyperpigmentation and hypopigmentation in the skin?
»	How is tinea versicolor diagnosed? Why is it difficult to culture this organism?
»	Does Malassezia cause any other skin disease?
»	What is tinea nigra?
»	What is a Majocchi’s granuloma?
»	What is piedra?
»	Name the organism most commonly isolated from cutaneous candidiasis.
»	How do candidal infections present clinically?
»	What factors predispose to candidiasis?
»	Which diseases are associated with adult-onset chronic mucocutaneous candidiasis?
»	Name the different classes of oral antifungal agents and their mechanisms of action.
»	Which hepatic cytochrome is affected by itraconazole, ketoconazole, and fluconazole?
»	Which drugs should be used with caution when using ketoconazole, itraconazole, or fluconazole? Why?
»	Which drugs are contraindicated when using azole antifungal agents and why?
»	Which oral antifungal agents can lower cyclosporine levels?
»	Which drugs can affect antifungal drug levels?
»	Which antifungal drugs have a limited spectrum of activity in the treatment of superficial fungal infections?

What is piedra?

Piedra refers to adherent deposits on the hair shaft caused by superficial fungal infections. Black piedra, which is caused by Piedraia hortae, presents as firm black nodules on the hair shaft. Trichosporon beigelii is the etiologic agent that produces white piedra, which results in the formation of less-adherent white concretions on the hair shaft. This organism has been reclassified into over six pathologic species, with the T. inkin and T. ovoides being the most common causes of white piedra in pubic hair.

Fitzpatrick JE: Superficial fungal skin diseases. In James WD, editor: Textbook of military medicine. Part III. Disease and the environment, Washington, DC, 1994, Office of the Surgeon General at Textbook of Military Medicine Publication, Borden Institute, Walter Reed Medical Center, pp 423–451.

Sobera JO, Elewski BE : Fungal infections. In Bolognia JL, Jorizzo JL, Rapini RP, et al, editors: Dermatology, New York, 2008, Mosby, pp 1135–1163.