We describe here in a case of a 41-year-old man, with diabetes mellitus, who presented manifestations of Kyrle's disease. Administration of metronidazole, 500 mg twice daily for 1 month, resulted in complete regression of skin lesions with no recurrence during 12 months of follow-up. This successful antibiotic treatment is to support the role of infectious agents (anaerobic bacteria) in the pathogenesis of Kyrle's disease.