A 55-year-old woman presented with a three-week history of a 1cm diameter lesion on her thumb.
She was a farmer and had spent the previous few weeks caring for many newborn lambs, which included bottle feeding and assisting difficult deliveries.
Over the two weeks since the lesion had appeared, there had been an initial increase in size, but this had now stopped. The lesion was painful. The patient had noticed similar lesions around the mouth of some of the lambs. She reported having similar lesions in the past, but these had usually resolved by this time.
She was otherwise fit and well. Apart from keeping the nodule covered, she had not treated it in any way.
This nodule is typical in orf, a viral (parapox virus) infection, which is widespread in sheep and goats. Transmission is either by direct contact with the animal or infected fomites.
The most commonly affected areas are the hands and index fingers, with the nodule appearing one week after contact. A low-grade fever may occur, which lasts three to four days. Antiseptics, dressings and immobilisation of affected fingers can be helpful. Any secondary bacterial infections should be treated with topical or oral antibiotics. The condition is self-limiting, with an average time to resolution of 35 days. In complicated cases, imiquimod can be useful.
- Milker's nodules
- Acute febrile neutrophilic dermatosis
Dr Stollery is a GP in Leicestershire and clinical assistant in dermatology at Leicester Royal Infirmary.