The dermatophytes include a number of fungi that attack the nails and skin. A presumptive etiologic diagnosis may be made by examining scrapings of the affected area microscopically in a wet mount of 10% KOH. Calcofluor white or similar fluorescent methods enhance detection. Definitive diagnosis is by culture, usually on an all-purpose medium such as Sabouraud’s agar, although some special media are available.