title: H1-antihistamine treatment in young atopic children: effect on urticaria.
abstract: BACKGROUND
  There are few published, randomized, double-masked, placebo-controlled, clinical trials of interventions for urticaria in the pediatric population.
  
  
  OBJECTIVE
  To study the effect of long-term treatment with the H1-antihistamine levocetirizine on urticaria in young atopic children.
  
  
  METHODS
  In the randomized, double-masked, parallel-group Early Prevention of Asthma in Atopic Children Study, children with atopic dermatitis aged 12 to 24 months at enrollment received levocetirizine, 0.125 mg/kg, or matching placebo twice daily for 18 months. On a diary card, the child's caregiver recorded the days on which urticaria was observed. This was validated by the study investigator and entered into the electronic case report form, along with any additional relevant information.
  
  
  RESULTS
  A total of 510 atopic children (mean +/- SEM age, 19.4 +/- 0.2 months) composed the intention-to-treat population. During the subsequent 18 months, 27.5% (70/255) of the children taking levocetirizine and 41.6% (106/255) of the children taking placebo experienced urticaria (P < .001). The mean +/- SEM number of urticaria episodes was 0.71 +/- 0.11 in those receiving levocetirizine and 1.71 +/- 0.25 in those receiving placebo (P < .001). The mean +/- SEM duration of urticaria episodes was 4.43 +/- 1.57 days in those receiving levocetirizine and 5.36 +/- 1.27 days in those receiving placebo (P < .001).
  
  
  CONCLUSIONS
  Urticaria is common in atopic toddlers and deserves recognition as an important disorder that occurs early in the atopic marathon. Regular long-term treatment with levocetirizine effectively prevents and treats urticaria in young children. The results of this study strengthen the evidence base for the use of relatively nonsedating, second-generation H1-antihistamines in the pediatric population.
authors.affiliation: Department of Pediatrics, Canadian Institutes of Health Research National Training Program in Allergy and Asthma, Faculty of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada. lmcniven@hsc.mb.ca
authors.forename: F Estelle R
authors.initials: FE
authors.lastname: Simons
mesh_terms: D017332:Cetirizine / Q000627:therapeutic use*; D002675:Child, Preschool; D004311:Double-Blind Method; D005260:Female; D039563:Histamine H1 Antagonists, Non-Sedating / Q000627:therapeutic use*; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000188:drug therapy; D007223:Infant; D008297:Male; D010879:Piperazines / Q000627:therapeutic use*; D013997:Time Factors; D016896:Treatment Outcome; D014581:Urticaria / Q000188:drug therapy*
chemical_list: D039563:Histamine H1 Antagonists, Non-Sedating; D010879:Piperazines; C472067:levocetirizine; D017332:Cetirizine