title: Azithromycin is more allergenic than clarithromycin in children with suspected hypersensitivity reaction to macrolides.
abstract: BACKGROUND
  Macrolides are considered safe antibiotics with reduced allergenic activity. However, studies on the safety of macrolides are scarce, particularly in children.
  
  
  OBJECTIVE
  The aim of this study was to assess the frequency of hypersensitivity reactions to clarithromycin and azithromycin in a group of children referred to our allergy unit for suspected macrolide allergy.
  
  
  METHODS
  We retrospectively reviewed the charts of 90 children aged 1-17 years with symptoms suggestive of hypersensitivity reaction to clarithromycin or azithromycin between December 31, 2008 and December 31, 2013. The allergy workup included skin tests (ie, skin prick tests and/or intradermal tests), determination of serum specific IgE (sIgE) to clarithromycin and azithromycin, and, if necessary to reach a diagnosis, oral provocation tests.
  
  
  RESULTS
  Seventy-seven children completed the allergy workup. A reaction to clarithromycin was recorded in 58 children (75.3%): 21 (36.2%) had a history of immediate reactions, and 37 (63.8%) had a history of nonimmediate reactions. A reaction to azithromycin was recorded in 19 children (24.6%): 6 (31.5%) had a history of immediate reaction, and 13 (68.42%) had a history of nonimmediate reaction. Positive results in skin tests and oral provocation tests with the suspect drug confirmed the diagnosis in 15.5% of reactions to clarithromycin (9 of 58) and in 47.3% of reactions to azithromycin (9 of 19) (P = .004).
  
  
  CONCLUSIONS
  A complete allergy workup enabled us to confirm a diagnosis of clarithromycin and azithromycin allergy in 15.5% and 47.3% of cases, respectively. Azithromycin was more allergenic than clarithromycin in children.
authors.forename: S
authors.initials: S
authors.lastname: Barni
authors.forename: D
authors.initials: D
authors.lastname: Butti
authors.forename: F
authors.initials: F
authors.lastname: Mori
authors.forename: N
authors.initials: N
authors.lastname: Pucci
authors.forename: M E
authors.initials: ME
authors.lastname: Rossi
authors.forename: A
authors.initials: A
authors.lastname: Cianferoni
authors.forename: E
authors.initials: E
authors.lastname: Novembre
mesh_terms: D000293:Adolescent; D000367:Age Factors; D000900:Anti-Bacterial Agents / Q000009:adverse effects*; D017963:Azithromycin / Q000009:adverse effects*; D015415:Biomarkers / Q000097:blood; D002648:Child; D002675:Child, Preschool; D017291:Clarithromycin / Q000009:adverse effects*; D004342:Drug Hypersensitivity / Q000097:blood / Q000175:diagnosis / Q000209:etiology* / Q000276:immunology; D005260:Female; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood; D007223:Infant; D007428:Intradermal Tests; D007558:Italy; D008297:Male; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012307:Risk Factors
chemical_list: D000900:Anti-Bacterial Agents; D015415:Biomarkers; D007073:Immunoglobulin E; D017963:Azithromycin; D017291:Clarithromycin