title: Immediate rhinoconjunctivitis induced by metamizole and metronidazole.
abstract: OBJECTIVE
  To report a case of immediate rhinoconjunctivitis induced by both metamizole and metronidazole.
  
  
  METHODS
  Skin-tests (prick and intradermal) were performed with metamizole, metronidazole, and espyramicine. Standard RAST was carried out with metamizole and metronidazole. Oral challenge tests were performed single blind with Rhodogil, metronidazole, espyramicine, metamizole, aspirin, and propyfenazone.
  
  
  RESULTS
  Both skin tests and RAST were negative. We also found that the patient tolerated therapeutic doses of espyramicine, aspirin, and propyfenazone. Challenges with Rhodogil, metamizole, and metronidazole elicited immediate rhinoconjunctivitis.
  
  
  CONCLUSIONS
  This is an exceptional case of immediate rhinoconjunctivitis induced by two unrelated drugs (metamizole and metronidazole). The pathogenic mechanism implicated in this process remains unclear. Inhibition of the cyclooxygenase pathway was excluded and we could not demonstrate the presence of specific IgE antibodies. Nevertheless, an immunologic or idiosyncratic mechanism could be responsible.
authors.affiliation: Allergy Unit, Hospital Virgen de la Luz, Cuenca, Spain.
authors.forename: B
authors.initials: B
authors.lastname: Añíbarro
authors.forename: J L
authors.initials: JL
authors.lastname: Fontela
mesh_terms: D000328:Adult; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000009:adverse effects*; D000994:Antitrichomonal Agents / Q000009:adverse effects*; D003231:Conjunctivitis / Q000139:chemically induced* / Q000276:immunology*; D004177:Dipyrone / Q000009:adverse effects*; D005260:Female; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000139:chemically induced* / Q000276:immunology*; D008795:Metronidazole / Q000009:adverse effects*; D011852:Radioallergosorbent Test; D012220:Rhinitis / Q000139:chemically induced* / Q000276:immunology*; D016037:Single-Blind Method; D012882:Skin Tests
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D000994:Antitrichomonal Agents; D008795:Metronidazole; D004177:Dipyrone