title: Dissociation between history and challenge in patients with physical urticaria.
abstract: BACKGROUND
  Physical urticaria is a subtype of chronic urticaria induced by a physical stimulus.
  
  
  OBJECTIVE
  To evaluate the consistency between a history of physical urticaria and results of challenge testing.
  
  
  METHODS
  Seventy-six subjects, ages 3 to 77 years old, were referred with the diagnosis of a physical urticaria and were evaluated by using challenge testing directed toward the presenting diagnosis, yet included other stimuli based on history. The majority of subjects were tested to 3 or more stimuli, thus 294 provocation tests were performed. Fifty-seven subjects were surveyed for the status of their physical urticaria at least 1 year after initial evaluation.
  
  
  RESULTS
  Of the 76 subjects with a positive history of a physical urticaria, 38% (n = 29) were challenge negative to the presenting diagnosis. Eight subjects within the challenge negative group reacted positively to additional testing, thus 28% (n = 21) remained negative to all challenge testing, which allowed discontinuation of medications and avoidance behavior. A negative challenge result was less likely with subjects who presented with cold-induced urticaria (25%), delayed pressure urticaria (25%), and dermatographism (29%), yet more common with cholinergic (65%) and solar urticaria (67%). A 1-year follow-up survey of 57 subjects was consistent with initial results. Nineteen of this subgroup were rechallenged for the presenting diagnosis, and the outcome was unchanged in 17 subjects and, in 2 subjects the urticaria had resolved.
  
  
  CONCLUSIONS
  The diagnosis by history of a physical urticaria should be verified by testing whenever possible and particularly if the condition is judged as severe and thus requires both significant life-style changes and pharmacologic intervention.
authors.affiliation: Laboratory of Allergic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Md. Electronic address: komarowh@niaid.nih.gov.
authors.forename: Hirsh D
authors.initials: HD
authors.lastname: Komarow
authors.affiliation: Laboratory of Allergic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Md.
authors.forename: Sarah
authors.initials: S
authors.lastname: Arceo
authors.affiliation: Clinical Research Directorate/Clinical Monitoring Research Program, Leidos Biomedical Research Inc, formerly SAIC-Frederick Inc, Frederick National Laboratory for Cancer Research, Frederick, Md.
authors.forename: Michael
authors.initials: M
authors.lastname: Young
authors.affiliation: Laboratory of Allergic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Md.
authors.forename: Celeste
authors.initials: C
authors.lastname: Nelson
authors.affiliation: Laboratory of Allergic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Md.
authors.forename: Dean D
authors.initials: DD
authors.lastname: Metcalfe
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D002908:Chronic Disease; D003080:Cold Temperature; D005080:Exercise Test; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010775:Photic Stimulation; D010812:Physical Stimulation; D011237:Predictive Value of Tests; D011312:Pressure; D011379:Prognosis; D012307:Risk Factors; D040242:Risk Reduction Behavior; D012720:Severity of Illness Index; D013997:Time Factors; D014466:Ultraviolet Rays; D014581:Urticaria / Q000175:diagnosis / Q000209:etiology* / Q000628:therapy; D055815:Young Adult
keywords: Challenge testing; Cholinergic; Cold; Delayed pressure; Dermatographism; Physical urticaria; Urticaria