Heat Contact Urticaria: A case report

Heat contact urticaria is very rare and it is characterized by the development of wheal limited to the areas of heat contact. We report a case of heat contact urticaria in a 65-year-old women. The wheal was induced by hot bathing, washing in hot water or leaning on hot radiators. Symptoms started within 5 minutes of exposure and lasted 30 to 60 minutes. She had no systemic symptoms. The clinical diagnosis of localized heat urticaria was confirmed by experimental induction of localized wheals. Our investigation showed that the threshold temperature needed for induction of the heat urticaria was 39°C. We tried to investigate the plasma levels of prostaglandin D₂ and blood histamine before and after heat challenge. The patient showed marked improvement after a combination treatment of desensitizing by repeated exposure to heat and indomethacine.