The syndrome of autoerythrocyte sensitization is characterized by painful ecchymotic lesions of the skin that develop in a very stereotypic manner. Onset occurs in a palm-sized skin region, usually on the limbs, with a stinging and burning sensation. After varying lengths of time, in general 2–6 hours, the skin becomes red, hot, oedematous and tender. This inflammatory phase may last anything up to twenty-four hours. Over the next few days the rubescent heated infiltration turns into an ecchymosis which spreads annularly at the same time as the tenderness and swelling diminish. Originally described by Gardner and Diamond (1955), thirty-one cases of the syndrome have now been reported. Up to the present all reported cases have come from North America and Australia and been confined to women with an age at onset of between 15 and 66 years.