Diagnostic biologique des dermatophytoses

Abstract

AbstractDermatophytoses are very common causes of consultation in dermatology. The diagnosis of these superficial infections, affecting the skin, nails and hair, is usually not clinically obvious and requires mycological analysis, especially for infections of the scalp and nails. Direct microscopic examination of clinical samples using clearing agents provides a quick response and should be combined with cultures on specific media. Histological analysis, which is considered the gold standard for the diagnosis of onychomycosis, is seldom performed and as direct examination, allows only visualisation of fungal elements without precise identification of the fungi. Accurate identification of the causative agent is necessary to initiate an appropriate treatment but also for setting prophylactic measures. However, conventional methods often lack sensitivity and species identification from cultures may require up to four weeks. Thus, the use of fluorochromes may greatly enhance the sensitivity of direct examination, as the use of culture media containing antifungal deactivators may enhance the sensitivity of cultures. Finally, despite the commercial availability of PCR-based kits, the biological diagnosis of dermatophytosis still relies on standard mycological procedures (direct examination and specific cultures), which remain the most informative and the least expensive procedures.