Non-dermatophyte Dermatoses Mimicking Dermatophytoses in Humans

Human dermatophytic cutaneous infections usually present as single or multiple slowly progressing annular erythemato-squamous lesions with a tendency to central healing on the hairless skin. In the intertriginous regions (feet, inguinal, axillar, submammary), dermatophytic colonisations and infections manifest as whitish, slightly hyperkeratotic, pruritic and sometimes fissurated lesions. On the scalp, dermatophytic infections commonly lead to single or multiple more or less inflammatory and alopecic lesions. On the plantar and palmar aspects of the feet and hand, dermatophytosis presents as an eczema-like chronic dermatosis. Abscess-like lesions may occur due to zoophilic dermatomycosis. Dermatophytic infections of the nails reveal ill-defined whitish-yellowish colorations of the distal end or the lateral aspects of the nails, sometimes combined with partial nail embrittlement or even complete destruction. Despite the ubiquity of dermatophytic skin infections and their usually highly typical clinical features, a differential diagnosis has to be considered, in particular when treatment is not efficient or when treatment resistance occurs. This review presents the differential diagnosis in terms of frequency as well as the diagnostic methods permitting the distinction of annular, intertriginous, alopecic, palmoplantar, abscess-like and onychodystrophic lesions.