Examen mycologique en dermatologie

Abstract

Dermatomycoses are dermatological infections very commonly encountered in private dermatological practice since they affect up to one third of the population. However, the symptoms are very often shared by other skin infections and disorders and may be highly atypical. It is thus impossible to make a diagnosis with any certainty on clinical grounds alone. For this reason, mycological diagnosis is essential to either confirm or rule out dermatomycosis, and is unavoidable when antifungal therapy is required for the treatment of ringworm of the scalp or beard, or for onychomycosis. It is also vital where therapy guided by the clinical appearance of lesions has failed or in the event of recurring skin lesions. Confirmation of mycosis enables antifungals to be initiated and a negative test warrants investigation for other underlying causes for the lesions seen. However, regardless of the mycological diagnostic technique employed, the quality of the results depends chiefly on the quality of sampling of the infected site, but also on the expertise of the microbiologist. Standard mycological testing remains the most informative, the least expensive and the sole examination capable of isolating the causative fungus irrespective of the type of mycosis, such as dermatophytosis, scytalidiosis, mould-induced ungual infection, candidiasis, or infections due to Malassezia sp. This is the only examination able to identify epidemiological variations. All other more recent techniques are either based upon simple demonstration of the fungal elements involved, without identification of the fungal species in question, or else they are reliant upon a fungal database that is generally highly incomplete.

Keywords: Candidiasis; Candidose; Dermatophytose; Dermatophytosis; Diagnostic mycologique; Mould-induced onychomycosis; Mycological diagnosis; Onychomycose à moisissure; Pityriasis versicolor; Scytalidiose; Scytalidiosis.