Background: The prevalence of various subtypes of urticaria in Japan has not been analyzed.
Methods: We have classified 260 (105 males and 155 females) out patients with urticaria based on the classification in Guidelines for the diagnosis and treatment of urticaria and angioedema" prepared by the Japanese Dermatological Association with slight modification.
Results: The urticaria in 200 out of 260 (76.9%) patients was idiopathic, and 101 (38.8%) patients showed more than one type of urticaria or angioedema. Among 146 patients with chronic urticaria, 90 (61.6%) were complicated by other types of urticaria; 59 (40.4%) by factitia, 29 (19.9%) by angioedema, and 12 (8.2%) by other types of urticaria. Deep pressure urticaria has been assumed as a rare type of urticaria in Japan, but was diagnosed in 5 patients with other types of urticaria.
Conclusion: Most of the subtypes of urticaria could be diagnosed mainly by history and physical examinations. Correct diagnosis of the subtypes of urticaria should be the basis of better understanding and the treatment of this disease.