Human orf. A diagnostic consideration?

We saw four unrelated cases of human orf infection over a 3-month period. Each patient had a clear-cut history of contact with sheep and developed a characteristic painful pustular lesion on the hand. There were no significant systemic symptoms. Examination of an aspirate by electron microscopy confirmed the diagnosis. The lesions resolved spontaneously within 6 weeks. Human orf infection occurs in North America, and although seldom reported, it should be considered in the diagnosis of cutaneous lesions in patients who have exposure to animals associated with it.