title: Double-blind placebo-controlled trial of dapsone in antihistamine refractory chronic idiopathic urticaria.
abstract: BACKGROUND
  Management of antihistamine refractory chronic idiopathic urticaria (CIU) has poorly defined therapeutic options.
  
  
  OBJECTIVE
  To evaluate the efficacy of dapsone (4,4'-diaminodiphenylsulfone) in antihistamine refractory CIU compared with placebo.
  
  
  METHODS
  Twenty-two patients with antihistamine refractory CIU were randomly assigned to 100 mg of dapsone daily or placebo for 6 weeks in a 14-week double-blind, placebo-controlled crossover trial. End points were measured from a daily diary that reflected the weekly hive score, the weekly itch score, and a visual analog scale (VAS) score. Secondary to a carryover effect, the first period results were analyzed as a parallel design that compared placebo with dapsone directly by using repeated-measures analysis.
  
  
  RESULTS
  After 6 weeks, the patients in the dapsone arm showed mean improvement over baseline in VAS (2.3 [95% CI, 0.6-4.1], P = .01), urticaria score (-3.5 [95% CI, -6.2 to -0.9], P = .01), and itch score (-4.8 [95% CI, -7.6 to -2.1], P = .001), whereas the placebo arm showed no improvement over baseline for VAS, urticaria, or itch scores. Dapsone showed greater improvement compared with placebo for itch (P = .047) and VAS (P = .04). Of the 22 patients, 3 showed complete resolution of hives and itch with dapsone, whereas 31% and 41% had ≥ 50% resolution of hives and itch, respectively. No serious adverse effects were observed with dapsone.
  
  
  CONCLUSIONS
  To our knowledge, this is the first double-blind, placebo controlled study of dapsone in CIU and indicates that dapsone has efficacy in patients with antihistamine refractory CIU.
authors.affiliation: Division of Allergy and Immunology, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas; Allergy, Asthma, and Immunology of North Texas, McKinney, Texas.
authors.forename: Matt
authors.initials: M
authors.lastname: Morgan
authors.affiliation: Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas.
authors.forename: Andrew
authors.initials: A
authors.lastname: Cooke
authors.affiliation: Division of Allergy and Immunology, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas; Chicago Lake Shore Allergy and Asthma, Chicago, Ill.
authors.forename: Laura
authors.initials: L
authors.lastname: Rogers
authors.affiliation: Division of Biostatistics, Department of Clinical Sciences, University of Texas, Southwestern Medical Center, Dallas, Texas.
authors.forename: Beverley
authors.initials: B
authors.lastname: Adams-Huet
authors.affiliation: Division of Allergy and Immunology, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas. Electronic address: dave.khan@utsouthwestern.edu.
authors.forename: David A
authors.initials: DA
authors.lastname: Khan
mesh_terms: D000328:Adult; D018926:Anti-Allergic Agents / Q000009:adverse effects / Q000627:therapeutic use*; D002908:Chronic Disease; D018592:Cross-Over Studies; D003622:Dapsone / Q000009:adverse effects / Q000627:therapeutic use*; D004311:Double-Blind Method; D004351:Drug Resistance; D005260:Female; D006634:Histamine H1 Antagonists / Q000627:therapeutic use; D006801:Humans; D008297:Male; D008875:Middle Aged; D014581:Urticaria / Q000188:drug therapy*
chemical_list: D018926:Anti-Allergic Agents; D006634:Histamine H1 Antagonists; D003622:Dapsone
keywords: Antihistamine; Chronic idiopathic urticaria; Dapsone; RCT; Urticaria