Atypical presentation of eczematiform dermatophytid secondary to Trichophyton rubrum onychomycosis: a case report and literature review

Abstract

Dermatophytids are inflammatory dermatological manifestations, due to immuno-allergic reactions and hypersensitivity to the antigens of a fungal pathogen. We report a rare case of dermatophytid secondary to Trichophyton rubrum onychomycosis, which is unusual due to the causative agent and also given the location and appearance of the lesions. This is a 54-year-old male, with no particular pathological history. He presented with recurrent eczematous and papular skin lesions on both lower limbs for 2 years, associated with neglected toenail onychomycosis, which preceded the skin lesions by 18 months. Biological investigations were unremarkable. Mycological samples were taken from skin lesions and nails of which the mycological examination revealed Trichophyton rubrum onychomycosis for nail samples, while that of the skin rash samples was negative. In view of this picture, which was suggestive of dermatophytid, the patient was prescribed terbinafine with a strong local corticosteroid, and the evolution under treatment was marked by progressive healing of skin lesions. This clinical case highlights an unusual pathology which the diagnosis is not always obvious and often misknowned by many practitioners.