Superficial Cutaneous Fungal Infections

Abstract In this chapter, we review cutaneous diseases caused by a variety of fungal pathogens infecting the skin, hair, and nails. These diseases are divided into the following classification based on level of invasion, host inflammatory response, and pathogen: (1) superficial mycoses, (2) dermatophytoses, (3) cutaneous disease caused by nondermatophyte moulds, and (4) cutaneous candidiasis. Superficial mycoses are characterized by fungal invasion into the superficial stratum corneum with little to no inflammatory response. Dermatophytoses are caused by dermatophytes, which are a closely related group of fungi that invade the full thickness of the stratum corneum and result in a host-mediated immune response. Several nondermatophyte moulds produce infections that mimic dermatophytoses. Cutaneous candidiasis results from invasion of deep layers of the skin by members of the Candida genus. Superficial mycoses are fungal infections of the skin and hair that invade only the most superficial layers and cause little or no inflammatory response. These mycoses include the malassezioses, tinea nigra, blacpiedra, and white piedra. Superficial invasion of the nail plate, so-called white superficial onychomycosis, is discussed in the Dermatophytoses section.