Microsporum nanum infection in hog farmers

Microsporum nanum is a dermatophyte that can cause disease in both man and animals and is most frequently associated with ringworm infection in pigs. Human infections are rare in the literature. Three new cases of human M. nanum infection are reported here. Two patients had inflammatory tinea faciei and one had tinea cruris. The patients were successfully treated with clotrimazole or miconazole cream, sometimes combined with griseofulvin. All three patients were hog farmers and lived in the same small rural area. Occupational exposure is suggested as the cause of infection.