title: Cholinergic urticaria, a new pathogenic concept: hypohidrosis due to interference with the delivery of sweat to the skin surface.
abstract: BACKGROUND
  Acetylcholine has been suspected to be a pathogenetic factor for cholinergic urticaria (CU), without definite evidence. In contrast, there are scattered reports of CU associated with acquired generalized hypohidrosis. We have recently examined 2 patients with CU in both of whom we noticed the presence of extensive hypohidrosis that occurred only in winter.
  
  
  OBJECTIVE
  In these 2 patients, acquired hypohidrosis due to superficial obstruction of the acrosyringium was suspected as the cause. Both case 1, a 22-year-old Japanese man, and case 2, a 21-year-old Japanese man, began to have anhidrosis and numerous red macules on their body whenever they felt hot in winter. These symptoms ceased to appear in summer.
  
  
  METHODS
  We studied histologically their lesional skin in addition to provocation tests for CU.
  
  
  RESULTS
  The diagnosis of CU was confirmed by the provocation of typical wheals after physical exercise in both cases. Histological study revealed findings suggestive of the presence of occlusion of the superficial acrosyringium.
  
  
  CONCLUSIONS
  We think that such a hypohidrosis due to occlusion of superficial sweat ducts may also play a role in many other patients with CU of unknown etiology that becomes exacerbated in winter when sweating is not a frequent event.
authors.affiliation: Department of Dermatology, Tohoku University School of Medicine, Sendai, Japan.
authors.forename: Hiromi
authors.initials: H
authors.lastname: Kobayashi
authors.forename: Setsuya
authors.initials: S
authors.lastname: Aiba
authors.forename: Tomoo
authors.initials: T
authors.lastname: Yamagishi
authors.forename: Muneo
authors.initials: M
authors.lastname: Tanita
authors.forename: Masahiro
authors.initials: M
authors.lastname: Hara
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Saito
authors.forename: Hachiro
authors.initials: H
authors.lastname: Tagami
mesh_terms: D000109:Acetylcholine / Q000378:metabolism*; D000328:Adult; D001341:Autonomic Nervous System / Q000503:physiopathology; D001707:Biopsy, Needle; D006801:Humans; D007007:Hypohidrosis / Q000150:complications* / Q000175:diagnosis; D008297:Male; D011379:Prognosis; D012621:Seasons; D012879:Skin Physiological Phenomena; D012882:Skin Tests; D013546:Sweating / Q000502:physiology; D014581:Urticaria / Q000209:etiology / Q000473:pathology* / Q000503:physiopathology
chemical_list: D000109:Acetylcholine