URTICARIA caused by heat, exertion and excitement is an uncommon dermatologic disease. The subject is covered only by a phrase or a sentence in such standard textbooks as those of Andrews,1 Sutton and Sutton2 and Ormsby and Montgomery3 under the general heading of "urticaria." Duke,4 who has pioneered the study of physical allergy, described the first case of urticaria due to heat and exertion in 1924 and proposed the name of "urticaria calorica" for this eruption. Hopkins, Kesten and Hazel5 reported observations on 15 patients, but did not discuss the incidence of this entity. Of the 22 cases herein reported, 3 patients were seen on the dermatologic service of the Three Hundred and Sixty-Fourth Station Hospital in Kyoto, Japan, between Dec. 5, 1945 and Feb. 18; 1946. The other 19 were seen between the latter date and June 5, at the Thirteenth General Hospital in