title: Association of acute urticaria with Mycoplasma pneumoniae infection in hospitalized children.
abstract: BACKGROUND
  Acute urticaria is a common and disturbing disorder in children and has a versatile etiology.
  
  
  OBJECTIVE
  To investigate the association of acute urticaria with Mycoplasma pneumoniae infection in hospitalized children.
  
  
  METHODS
  Hospitalized children with acute urticaria from Taiwan who did not respond to antihistamine treatment and avoidance of food allergens were studied from February 1, 2006, to July 31, 2007. These patients with urticaria were compared with those who had other respiratory tract diseases and were classified into 2 groups: urticaria patients with and without M pneumoniae infection. The presence of M pneumoniae infection was determined by positive serologic findings.
  
  
  RESULTS
  Sixty-five patients with acute urticaria and 49 patients with other respiratory tract diseases were enrolled in this study. Patients with urticaria had significantly less febrile duration but significantly higher platelet and lymphocyte counts than those with other respiratory tract diseases. Of the 65 patients with urticaria, 21 (32%) showed serologic evidence of M pneumoniae infection. Patients with M pneumoniae-associated urticaria received azithromycin treatment and needed a shorter time for improvement (P = .01) and complete resolution (P = .04). The total IgE levels and the results of specific IgE tests were not significantly different between urticaria patients with and without M pneumoniae infection.
  
  
  CONCLUSIONS
  This study found that in Taiwan one-third of acute childhood urticaria leading to patient hospitalization was related to M pneumoniae infection. Therefore, children with urticaria who are not responding to antihistamine treatment and abstinence from food allergens should be encouraged to undergo serologic examinations for M pneumoniae to diagnose this antibiotic-responsive disorder.
authors.affiliation: Division of Pediatric Allergy and Immunology, Department of Pediatrics, Chang Gung Memorial Hospital-Kaohsiung Medical Center, Chang Gung University, Kaohsiung, Taiwan.
authors.forename: Chih-Chiang
authors.initials: CC
authors.lastname: Wu
authors.forename: Ho-Chang
authors.initials: HC
authors.lastname: Kuo
authors.forename: Hong-Ren
authors.initials: HR
authors.lastname: Yu
authors.forename: Lin
authors.initials: L
authors.lastname: Wang
authors.forename: Kuender D
authors.initials: KD
authors.lastname: Yang
mesh_terms: D015746:Abdominal Pain / Q000150:complications; D000410:Alanine Transaminase / Q000097:blood; D000485:Allergens / Q000276:immunology; D001219:Aspartate Aminotransferases / Q000097:blood; D017963:Azithromycin / Q000627:therapeutic use; D001772:Blood Cell Count; D002097:C-Reactive Protein / Q000378:metabolism; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D005260:Female; D005334:Fever / Q000097:blood / Q000150:complications; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood / Q000276:immunology; D007902:Length of Stay / Q000706:statistics & numerical data; D008297:Male; D011019:Pneumonia, Mycoplasma / Q000097:blood / Q000150:complications* / Q000175:diagnosis / Q000188:drug therapy; D012141:Respiratory Tract Infections / Q000097:blood / Q000150:complications; D013624:Taiwan; D014581:Urticaria / Q000097:blood / Q000175:diagnosis / Q000209:etiology*; D014839:Vomiting / Q000150:complications
chemical_list: D000485:Allergens; D007073:Immunoglobulin E; D017963:Azithromycin; D002097:C-Reactive Protein; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase