A case of distal subungual onychomycosis of the big toe due to Microsporum canis is reported in a 69-year-old male asthma patient who had been treated with systemic corticosteroids for the last 3 years. The nail infection was contracted from a cat who was a healthy carrier. The patient was treated successfully with intermittent itraconazole therapy.

A case of distal subungual onychomycosis of the big toe due to Microsporum canis is reported in a 69-year-old male asthma patient who had been treated with systemic corticosteroids for the last 3 years. The nail infection was contracted from a cat who was a healthy carrier. The patient was treated successfully with intermittent itraconazole therapy.