A dermatophytoma is a mass of hyphae that is observed at direct examination, it responds poorly to treatment with antifungal drugs, some authors have proposed that it is actually a biofilm. This pathology is underdiagnosed, and its true incidence is unknown.

This study presents the clinical findings of dermatophytoma in HIV/AIDS patients from Colombia presenting onychomycosis.

A transversal observational descriptive study was carried out in a third level university hospital. One hundred thirty HIV positive patients diagnosed using ELISA and Western Blot that presented nail lesions on their hands and/or feet compatible with onychomycosis were included. Samples taken from affected nails were observed in direct examination with KOH and seeded onto Sabouraud agar, mycosel agar and dextrose-potato agar. Molds were identified based on macroscopic and microscopic characteristics.

Six (4.6%) individuals presented dermatophytoma. Average age was 43 years (range 33–50); nails more commonly affected (5/6) were on the toes, principally the hallux. Clinical manifestations included a yellow or white, rounded or linear dense area on the nail. Superficial white onychomycosis was present in 83.3% of the patients. Fungal cultures were obtained in only 5 patients; Trichophyton mentagrophytes complex was found in 2 individuals while T. rubrum, T. tonsurans and Epidermophyton floccosum were in the other 3. Average cell count for CD4⁺ T lymphocytes was 86.8 cells/mm³ (range 9–282).

This is the first report in Colombia of dermatophytoma in HIV/AIDS patients, most of them had a CD4+ T lymphocytes count less than 200 cells/mm3. Several clinical forms of onychomycosis were observed, the most frequent was the white superficial onychomycosis.