title: Oral drug challenges in non-steroidal anti-inflammatory drug-induced urticaria, angioedema and anaphylaxis.
abstract: BACKGROUND
  Urticaria, angioedema and anaphylaxis are common adverse reactions to non-steroidal anti-inflammatory drugs (NSAIDs).
  
  
  OBJECTIVE
  To investigate the clinical characteristics of NSAID-induced acute hypersensitivity reactions with structured oral drug challenges.
  
  
  METHODS
  Patients with NSAID-induced urticaria, angioedema or anaphylaxis were challenged with either the homologous NSAID to confirm diagnosis or a heterologous NSAID to investigate cross-reactivity. Data were analysed retrospectively and supplemented by a telephone questionnaire.
  
  
  RESULTS
  Sixty-eight patients (mean age 48.3, 53 females) reported a total of 75 instances of NSAID-induced reactions of which 64% were purely cutaneous and 36% were systemic anaphylaxis. Ibuprofen was the most frequent cause of reactions (35%), however, diclofenac was the most frequent cause of anaphylaxis (48%). Seventeen out of 40 (43%) homologous NSAID challenges were positive; presentation with anaphylaxis or reaction to diclofenac predicted a positive challenge. Only 7 of 28 (25%) of heterologous NSAID challenges were positive. Structured challenges enabled us to identify 23 (34%) patients with selective reactivity to a single NSAID, 19 (28%) patients with cross-reactivity to multiple NSAIDs and 23 (34%) patients in whom NSAID hypersensitivity was not reproduced. Selective reactors presented most often with anaphylaxis and some had a background of beta-lactam antibiotic allergy. Cross-reactive patients often had a background of chronic urticaria and presented with milder reactions.
  
  
  CONCLUSIONS
  In the absence of a reliable in vitro test, structured drug challenges allow identification of selective and cross-reactive NSAID hypersensitivity syndromes. NSAID-induced anaphylaxis is often associated with selective hypersensitivity and patients may not need to avoid other NSAIDs.
authors: Greenslopes Private Hospital, Greenslopes, Queensland, Australia.
authors: T
authors: T
authors: Chaudhry
authors: P
authors: P
authors: Hissaria
authors: M
authors: M
authors: Wiese
authors: R
authors: R
authors: Heddle
authors: F
authors: F
authors: Kette
authors: W B
authors: WB
authors: Smith
mesh_terms: D000082:Acetaminophen / Q000009:adverse effects; D000293:Adolescent; D000328:Adult; D000368:Aged; D000707:Anaphylaxis / Q000139:chemically induced*; D000799:Angioedema / Q000139:chemically induced*; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000009:adverse effects*; D001241:Aspirin / Q000009:adverse effects; D004008:Diclofenac / Q000009:adverse effects; D005260:Female; D006801:Humans; D007052:Ibuprofen / Q000009:adverse effects; D008297:Male; D008875:Middle Aged; D014581:Urticaria / Q000139:chemically induced*; D055815:Young Adult
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D004008:Diclofenac; D000082:Acetaminophen; D001241:Aspirin; D007052:Ibuprofen