title: Anti-Amoxicillin Immunoglobulin E, Histamine-2 Receptor Antagonist Therapy and Mast Cell Activation Syndrome Are Risk Factors for Amoxicillin Anaphylaxis.
abstract: BACKGROUND
  β-Lactam antibiotics (mainly amoxicillin, AX) are the drugs that most frequently induce systemic drug allergy reactions.
  
  
  OBJECTIVE
  We attempted to identify the risk factors associated with systemic reactions to AX.
  
  
  METHODS
  All patients who were referred to our department for suspected hypersensitivity reactions to AX over a 6-month period were evaluated for anti-AX immunoglobulin E (IgE) levels and skin-test positivity for β-lactams. Age, sex, concomitant diseases, therapies, total IgE, serum tryptase levels and signs and symptoms suggesting mast cell activation syndrome (MCAS) were analyzed in relation to the severity of the reaction in accordance with the Mueller classification.
  
  
  RESULTS
  Sixty-seven patients were selected: 39 with mild reactions such as cutaneous or gastrointestinal symptoms (grades I and II) and 28 with severe systemic reactions (grades III and IV). Anti-AX IgE levels and total IgE were significantly higher in severe reactions than in mild ones (p < 0.00005, p = 0.0037). Treatment with histamine-2 receptor antagonists (anti-H2) was significantly related to severe reactions (p = 0.007). No significant correlations were found between the severity of the reactions and dyslipidemia or levels of angiotensin-converting enzyme and tryptase.
  
  
  CONCLUSIONS
  Anti-AX IgE levels were the most significant immunological parameter distinguishing patients who presented with severe reactions to AX and those with mild reactions. Higher values of total IgE, the use of gastroprotective drugs and signs and symptoms suggesting an MCAS significantly increased the odds ratio of having a severe reaction. The risk of serious adverse reactions to AX increased in older patients and in males, but this trend was not significant.
authors.affiliation: Allergology and Immunology Unit, Niguarda Ca' Granda Hospital, Milan, Italy.
authors.forename: Elide Anna
authors.initials: EA
authors.lastname: Pastorello
authors.forename: Chrysi
authors.initials: C
authors.lastname: Stafylaraki
authors.forename: Corrado
authors.initials: C
authors.lastname: Mirone
authors.forename: Donatella
authors.initials: D
authors.lastname: Preziosi
authors.forename: Maria Gloria
authors.initials: MG
authors.lastname: Aversano
authors.forename: Ambra
authors.initials: A
authors.lastname: Mascheri
authors.forename: Laura Michelina
authors.initials: LM
authors.lastname: Losappio
authors.forename: Valeria
authors.initials: V
authors.lastname: Ortolani
authors.forename: Michele
authors.initials: M
authors.lastname: Nichelatti
authors.forename: Laura
authors.initials: L
authors.lastname: Farioli
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000658:Amoxicillin / Q000009:adverse effects* / Q000276:immunology; D000707:Anaphylaxis / Q000139:chemically induced / Q000276:immunology*; D004342:Drug Hypersensitivity / Q000097:blood / Q000276:immunology*; D005260:Female; D006635:Histamine H2 Antagonists / Q000009:adverse effects / Q000276:immunology; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood*; D008297:Male; D008407:Mast Cells / Q000276:immunology*; D008875:Middle Aged; D012307:Risk Factors; D055815:Young Adult
chemical_list: D006635:Histamine H2 Antagonists; D007073:Immunoglobulin E; D000658:Amoxicillin