Étude des dermatophytes d’intérêt médical responsables des mycoses du cuir chevelu, de la peau et des ongles chez l’homme

Abstract

Dermatophytes are filamentous fungi commonly found in the environment, belong to the genera Microsporum, Trichophyton, and Epidermophyton. From a taxonomic point of view, their sexual reproduction classifies them as Ascomycetes, more precisely in the genus Arthroderma and the order Onygenales. These fungi show a strong adaptation to parasitic life due to their ability to degrade keratin, which makes them responsible for superficial skin infections known as dermatophytoses, affecting both humans and animals. Dermatophytes are among the most common types of fungal skin infections in humans. They manifest as localized lesions on glabrous skin, the palms of the hands, soles of the feet, skin folds (intertrigo), as well as on the hair or (scalp ringworm, folliculitis, kerion), and also on the nails(onychomycosis). In healthy individuals, these infections are generally mild but can become chronic and cases of immunosuppression, the infection may extend into the dermis or even reach internal organs, causing a severe condition known as dermatophytic disease. The clinical presentation of dermatophytoses are very varied and may sometime resemble other dermatological diseases. This highlights the importance of mycological examination in the laboratory using collected samples before initiating systemic treatment, especially in the case of onychomycosis. For the Treatment of scalp ringworm, griseofulvin is recommended as a specific treatment. In contrast, terbinafine is considerd the treatment of choice for onycgomycosis. Topical treatments mainly include antifungals from the azole family, as well as terbinafine or ciclopiroxolamine. Prevention is essentially based on personal and collective hygiene measures, especially in public places such as swimming pools and communal baths. In cases of human-to-human (anthropophilic) transmission of scalp ringworm, it is no longer necessary to exclude the child from school if treatment has been started and is properly followed, unlike infection of animal origin.