Generalized cold urticaria: detection of heat-sensitive passive transfer substance active at moderate temperature

An 11–year-old girl presented with generalized weal formation of 8 months' duration which occurred when she was cooled at rest or after physical effort. The ice cube test was only slightly positive. Injection of the patient's serum into her arm skin and into the skin of two volunteers produced immediate weals. This passive transfer reaction occurred most strongly at skin temperatures around 30 °C but not at 40 °C. The weal producing substance was provisionally identified as an unusual immunoglobulin M(IgM) by gel filtration, immunoadsorption and physicochemical treatments.