title: Clinical presentation and time course in hypersensitivity reactions to beta-lactams.
abstract: BACKGROUND
  beta-lactam hypersensitivity reactions are classified as immediate or nonimmediate. Diagnosis is usually based upon skin tests and provocation challenges.
  
  
  OBJECTIVE
  The time course of the reactions in proven beta-lactam hypersensitivities was studied and then correlated with the symptoms to determine the relationship between the clinical presentations and the time course.
  
  
  METHODS
  All of the patients who consulted between 1996 and 2004 for a suspected beta-lactam hypersensitivity reaction were studied. Two hundred and ten patients with a proven hypersensitivity reaction diagnosed according to the European Network on Drug Allergy were included in the present study.
  
  
  RESULTS
  Of the patients, 36.7% had urticaria as a single symptom, 19.1% anaphylaxis without shock, 17.6% anaphylactic shock and 19.1% maculopapular exanthema. Anaphylactic shock and anaphylaxis mostly occurred within 1 h after drug administration. Exanthema mainly occurred after 24 h. Urticaria as a single symptom occurred at any time. A firm diagnosis was determined using immediate-reading skin prick (10.0%) and intradermal tests (38.1%), late-reading skin tests (19.1%) or provocation tests (32.9%).
  
  
  CONCLUSIONS
  Depending on the time course of the reaction, three clinical groups were identified: anaphylaxis and anaphylactic shock (immediate reaction); maculopapular exanthema (late reaction) as well as urticaria (immediate and late reaction).
authors.affiliation: Exploration des Allergies, Service des Maladies Respiratoires, Hôpital Arnaud de Villeneuve, University Hospital of Montpellier; INSERM U454-IFR3, Hôpital Arnaud de Villeneuve, Montpellier, France.
authors.forename: P J
authors.initials: PJ
authors.lastname: Bousquet
authors.forename: V
authors.initials: V
authors.lastname: Kvedariene
authors.forename: H-B
authors.initials: HB
authors.lastname: Co-Minh
authors.forename: P
authors.initials: P
authors.lastname: Martins
authors.forename: M
authors.initials: M
authors.lastname: Rongier
authors.forename: B
authors.initials: B
authors.lastname: Arnoux
authors.forename: P
authors.initials: P
authors.lastname: Demoly
mesh_terms: D000293:Adolescent; D000328:Adult; D000707:Anaphylaxis / Q000209:etiology / Q000276:immunology; D000900:Anti-Bacterial Agents / Q000009:adverse effects* / Q000276:immunology; D002648:Child; D015331:Cohort Studies; D004342:Drug Hypersensitivity / Q000175:diagnosis* / Q000276:immunology; D005076:Exanthema / Q000209:etiology / Q000276:immunology; D005260:Female; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000175:diagnosis / Q000276:immunology; D008297:Male; D008875:Middle Aged; D012882:Skin Tests; D013997:Time Factors; D014581:Urticaria / Q000209:etiology / Q000276:immunology; D047090:beta-Lactams / Q000009:adverse effects* / Q000276:immunology
chemical_list: D000900:Anti-Bacterial Agents; D047090:beta-Lactams