A patient presenting with a hand pustule is a phenomenon encountered worldwide requiring careful history-taking. Some occupations, activities, and various religious practices (eg, Eid al-Adha, Passover, Easter) have been implicated worldwide in orf infection. In the United States, orf virus usually is spread from infected animal hosts to humans. Herein, we review the differential for a single hand pustule, which includes both infectious and noninfectious causes. Recognizing orf virus as the etiology of a cutaneous hand pustule in patients is important, as misdiagnosis can lead to unnecessary invasive testing and/or treatments with suboptimal clinical outcomes.
Case Series
When conducting a search for orf virus cases at our institution (University of Iowa Hospitals and Clinics, Iowa City, Iowa), 5 patient cases were identified.
Patient 1—A 27-year-old otherwise healthy woman presented to clinic with a tender red bump on the right ring finger that had been slowly growing over the course of 2 weeks and had recently started to bleed. A social history revealed that she owned several goats, which she frequently milked; 1 of the goats had a cyst on the mouth, which she popped approximately 1 to 2 weeks prior to the appearance of the lesion on the finger. She also endorsed that she owned several cattle and various other animals with which she had frequent contact. A biopsy was obtained with features consistent with orf virus.
Patient 2—A 33-year-old man presented to clinic with a lesion of concern on the left index finger. Several days prior to presentation, the patient had visited the emergency department for swelling and erythema of the same finger after cutting himself with a knife while preparing sheep meat. Radiographs were normal, and the patient was referred to dermatology. In clinic, there was a 0.5-cm fluctuant mass on the distal interphalangeal joint of the third finger. The patient declined a biopsy, and the lesion healed over 4 to 6 weeks without complication.
Patient 3—A 38-year-old man presented to clinic with 2 painless, large, round nodules on the right proximal index finger, with open friable centers noted on physical examination (Figure 1). The patient reported cutting the finger while preparing sheep meat several days prior. The nodules had been present for a few weeks and continued to grow. A punch biopsy revealed evidence of parapoxvirus infection consistent with a diagnosis of orf.
FIGURE 1. Two erythematous to yellowish, crateriform, exophytic nodules with secondary pustulation, central erosion, and serosanguineous drainage on the right second interphalangeal joint and proximal finger.
Patient 4—A 48-year-old man was referred to our dermatology clinic for evaluation of a bleeding lesion on the left middle finger. Physical examination revealed an exophytic, friable, ulcerated nodule on the dorsal aspect of the left middle finger (Figure 2). Upon further questioning, the patient mentioned that he handled raw lamb meat after cutting the finger. A punch biopsy was obtained and was consistent with orf virus infection.
FIGURE 2. A 2-cm, well-defined, erythematous plaque with overlying erosion, serosanguineous drainage, and peripheral hyperpigmentation on the distal third finger.
Patient 5—A 43-year-old woman presented to clinic with a chronic wound on the mid lower back that was noted to drain and crust over. She thought the lesion was improving, but it had become painful over the last few weeks. A shave biopsy of the lesion was consistent with orf virus. At follow-up, the patient was unable to identify any recent contact with animals.