[Clinical problems in medical mycology: Problem number 50].

We present the case of a 34 year-old man, HIV-positive, who had suffered a disseminated histoplasmosis treated with amphotericin B one year before his admission. He was admitted at the Infectious Diseases Muñiz Hospital with a non-lithiasic chlolecystitis. During the clinical examination perigenital skin lesions compatible with tinea cruris, as well as proximal subungual onychomycoses of toenails, were observed. Microsporum gypseum was isolated from both types of lesions. Oral terbinafine led to a good clinical response. Treatment prescription was a big challenge in this patient because he was receiving HAART and itraconazole, and there was scarce experience in the treatment of nail infections due to M. gypseum.