Conduite diagnostique à tenir devant une alopécie

Identifying the etiology of alopecia is a multi-staged process including medical history, physical examination and dermoscopy, in order to classify alopecia: localized or diffuse ; cicatricial or not cicatricial ; genetic or not. This classification has some limits : several hair-loss disorders can have different clinical aspects. The most frequent clinical situation for mycologist is localized squamous alopecia in which differential diagnosis of ringworm must be considered including psoriasis, pityriasis amiantacea, cutaneous lymphoma and lupus. In some particular clinical presentations, histological or infectious skin specimens may provide valuable information regarding their etiology.