ABSTRACT
The term ‘dermatophytes’ is used to describe infections of the skin, hair and nails due to a group of related mold-like filamentous fungi. There are three genera of dermatophytes – Trichophyton, Microsporum and Epidermophyton – which contain 40 or more species, of which 11 are common causes of human infection. Dermatophytes are aerobic fungi that produce several proteases that digest scleroproteins, e.g. keratin, which permits colonization and invasion of the stratum corneum of the skin, the hair shaft (endothrix) and the nail. Although dermatophytes are not part of the normal skin flora, they are well adapted to infect the skin, because they can use keratin as a food source. Dermatophytes do not infect mucosal surfaces. Dermatophytoses are referred to as tinea infections and are named for the body site involved: tinea corporis (glabrous skin of the body), tinea capitis (scalp, eyebrows, eye lashes), tinea cruris (groin), tinea manuum (hand), tinea pedis (feet) and tinea unguium (nails). Different species can infect multiple sites and a single skin site can be infected by members of all three genera.
