[Three cases of erythma ab igne (EAI) in patients with eating disorders]

Erythema ab igne (EAI) is a reticulated pigmented dermatosis, which is caused by repetative and prolonged moderate heat exposure insufficient to produce a burn. We report here three cases of EAI in female patients with eating disorders (two with anorexia nervosa and one with bulimia nervosa) who presented with EAI on the abdomen as well as on the thighs and forearms. The clinical picture was characterized by asymptomatic reticular and macular hyperpigmentation and telangiectases without sequamation. The patients admitted the frequent and sometimes over night use of hot water bottles with the aim to reduce a general feeling of cold and to alleviate an aversive feeling of fullness after food intake. It is well known that patients with eating disorders have an increased pain threshold which might have contributed to the prolonged heat exposure. The patients were advised to stop using the hot water bottles. In two patients the EAI progressively cleared over the next 8 weeks; however, without complete remission. The third patient continued to regularly use the hot water bottle and the EAI persisted. The skin changes may persist a long time or even become permanent. EAI is accepted as a precancerous lesion and monitoring of permanent skin changes is advised. While historically EAI was seen in people sitting next to a stove or fire, a modern cause of EAI is the regular and prolonged use of laptop computers on the thighs ("laptop-thighs"). Since there is no effective treatment, the most effective measure is immediate removal of the heat source.