Erythema ab igne in cancer patients.

Five cancer patients were observed to have the skin change erythema ab igne (EAI) associated with painful underlying lesions, for which they had been applying local heating with hot-water bottles. In 4 cases the pain was produced by metastases and in one by the primary tumour. The EAI may be seen directly over the lesion or in an area of pain referral. In cancer patients it may be a helpful localizing sign, and in all patients (apart from the anterior lower legs of old people) it is very suggestive of a serious underlying cause.