title: Patch testing and sensitization to multiple drugs.
abstract: BACKGROUND
  Adverse drug reactions pose an increasing diagnostic challenge in hospitals and in outpatient clinics. When consecutive or repeated allergic drug eruptions are suspected, patch testing is a useful diagnostic tool for determining the causative drugs.
  
  
  OBJECTIVE
  The aim of the study was to identify patient cases with multiple delayed-type drug sensitizations by using patch testing.
  
  
  METHODS
  Eight hundred and eleven patients with suspected drug allergy were patch tested during a 9-year period.
  
  
  RESULTS
  Multiple delayed drug sensitizations were found in 12% of those patients with positive results in drug patch testing.
  
  
  CONCLUSIONS
  Drug patch testing is useful in cutaneous adverse drug reactions where multiple drugs are suspected. Multiple drug sensitizations can be found in a proportion of patients who have delayed drug allergies. In addition to drug reactions with eosinophilia and systemic symptoms, these patients may have repeated exanthemas or contact dermatitis.
authors.affiliation: Department of Dermatology, Turku University Hospital, 20521, Turku, Finland.
authors.forename: Jussi
authors.initials: J
authors.lastname: Liippo
authors.forename: Kati
authors.initials: K
authors.lastname: Pummi
authors.forename: Ulla
authors.initials: U
authors.lastname: Hohenthal
authors.forename: Kaija
authors.initials: K
authors.lastname: Lammintausta
mesh_terms: D000293:Adolescent; D000328:Adult; D000485:Allergens / Q000008:administration & dosage / Q000276:immunology; D003429:Cross Reactions; D017449:Dermatitis, Allergic Contact / Q000175:diagnosis* / Q000209:etiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010328:Patch Tests / Q000379:methods*
chemical_list: D000485:Allergens
keywords: adverse drug reactions; cross-reactions; multiple sensitization to systemic drugs; patch test