igne skin lesions. Diagnosis Differential diagnosis Livedo reticularis Vasculitis Treatment Discontinuing contact with the heat source is the initial treatment of erythema ab igne. If the area is only mildly affected with slight redness, the condition may resolve after a few months. If the condition is severe and the skin pigmented and atrophic, then it is unlikely to resolve. In this case, there is a possibility that a squamous cell carcinoma or a neuroendocrine carcinoma such as a Merkel cell carcinoma may form. If there is a persistent sore that does not heal or a growing lump within the rash, a skin biopsy should be performed to rule out the possibility of skin cancer. If the erythema ab igne lesions demonstrate pre-cancerous changes, the use of 5-fluorouracil cream has been recommended. Abnormally pigmented skin may persist for years. Treatment with topical tretinoin or laser treatment may improve the appearance. Epidemiology Erythema ab igne was once commonly seen in the elderly who stood or sat closely to open fires or electric heaters; however, erythema ab igne has been reported in both young and elderly individuals. Women have a higher incidence of erythema ab igne than men. Although wide use of central heating has reduced the overall incidence of erythema ab igne, it is still sometimes found in people exposed to heat from other sources such as heating pads, space heaters, hot water bottles, and electronic devices. References External links New England Journal of Medicine Image Challenge Skin conditions resulting from physical factors