Cutaneous alternariosis in a cat.

A 10-year-old male domestic shorthaired cat had a chronic, slowly enlarging subcutaneous mass on the right side of its nose. At the time of presentation, the nasal airflow was severely impeded on the affected side. The cat had been treated medically with various drugs. Oral itraconazole had been the most effective in reducing the size of the mass, but had caused hepatotoxicity and had to be withdrawn. The mass was finally removed surgically, and a diagnosis of granulomatous cellulitis caused by Alternaria alternata (phaeohyphomycosis) was established, based on histopathology and fungal isolation. There has been no recurrence of the lesion after 21 months and the cat remains clinically well at the time of writing. Subcutaneous phaeohyphomycosis caused by A alternata has not, to the authors' knowledge, been previously described in small domestic animals in the UK.