A case of cold urticaria due to a serum factor belonging to the IGE class.

A case of cold urticaria showing a positive Prausnitz-Kustner (P-K) reaction was studied. The results obtained were as follows: 1) the P-K reaction was positive, 2) skin fixation time was 21 days, 3) the P-K reaction could be blocked by heating the serum for 2 hours at 56°C, and 4) the P-K reaction became negative after adsorption of IgE from the serum. These data suggest that the serum factor responsible for cold urticaria in this case belongs to the IgE class. The effect of histamine liberator 48/80, histological examination of the skin and results of the estimation of serum histamine concentration by a fluorometric method all suggest that this wheal formation is due to a histamine release from mast cells in the skin.