Dermatophyte infections are common superficial fungal infections involving the scalp (tinea capitis), body (tinea corporis), feet (tinea pedis), crural fold (tinea cruris), and nails (onychomycosis). Infection is very common in healthy individuals, but can be varied and atypical in patients with HIV. HIV/AIDS patients also can demonstrate a much more severe and extensive form of disease. Three different dermatophytes are the usual source of infection: epidermophyton, trichophyton, and microsporum.
Tinea capitis is seen as an enlarging scaling patch on the scalp that may progress to a kerion. The initial lesion can be overlooked until alopecia is present. Untreated permanent scarring can occur. Tinea pedis is the most common dermatophyte infection seen in practice. Usually self-limited, intermittent, recurrent, and intensely pruritic, these lesions can often be secondarily infected due to mechanical irritation. Tinea corporis is the most common fungal infection seen in HIV patients. Usually, it begins as an intensely pruritic, oval scaling erythematous lesion that spreads centrifugally and can merge with other lesions. Tinea cruris is an infection involving the crural fold, much more common in men than women. It usually begins as a macular patch on the inner thigh, opposite the scrotal sac.
Tinea Infection. Tinea infection involving the scalp, neck, and upper back of this HIV-infected patient. (Photo contributor: Seth W. Wright, MD.)
Management and Disposition
Tinea capitis responds to griseofulvin and other oral agents such as terbinafine, itraconazole, or fluconazole. Treatment usually is carried out for at least 3 weeks, with topical treatments ineffective. Tinea pedis can usually be treated with a topical antifungal cream for 4 weeks. Often patients have tried outpatient, over-the-counter antifungal medications without success. Tinea corporis often responds to daily application of topical antifungal medications; however, the systemic oral agents described above are also effective. Tinea cruris usually responds to topical antifungal medications.
Confirming the diagnosis with a KOH preparation is important before initiating therapy, especially in diffuse disease. Often HIV patients suffer from a variety of skin infections that mimic dermatophyte lesions (eczema).
Athletes are especially at risk when close skin-to-skin contact occurs (wrestling, football). Oral treatment in these cases is preferred.
Some dermatophyte infections fluoresce under the Wood lamp examination.
Tinea Corporis. Tinea infection involving the lower back and buttocks of the patient in Fig. 20.38. (Photo contributor: Seth W. Wright, MD.)