title: Low yield for extended reading of patch tests with topical corticosteroids.
abstract: BACKGROUND
  On the basis of reports that up to 30% of patch test reactions are missed if an extended reading is not performed, we required that patients who were being patch tested with the corticosteroid series return for a reading at least 1 week after placement of the allergens.
  
  
  OBJECTIVE
  To report our institutional experience with extended readings (day 7 or beyond) of patch test reactions to the corticosteroid series.
  
  
  METHODS
  We retrospectively reviewed patch test reactions to corticosteroids since extended readings were implemented (April 2001 to June 2004).
  
  
  RESULTS
  A total of 135 patients were patch tested with 1,656 corticosteroid allergens. On day 5, five patients had five positive patch test reactions; by the time of the extended reading, no new reactions had developed in these patients. Of the patients with no reactions on day 5, two had a positive result at the extended reading: each had a relevant reaction to budesonide 0.1%, one on day 7 and the other on day 9.
  
  
  CONCLUSIONS
  Only 2 reactions (to 1,656 corticosteroids) became apparent at the extended reading. Extended readings were of limited value in our experience.
authors.affiliation: Department of Dermatology and the Division of Biostatistics, Mayo Clinic, Rochester, MN, USA.
authors.forename: Mark D P
authors.initials: MD
authors.lastname: Davis
authors.forename: Donna M
authors.initials: DM
authors.lastname: Richardson
authors.forename: Sara A
authors.initials: SA
authors.lastname: Farmer
mesh_terms: D000287:Administration, Topical; D000305:Adrenal Cortex Hormones / Q000008:administration & dosage / Q000009:adverse effects*; D017449:Dermatitis, Allergic Contact / Q000175:diagnosis* / Q000209:etiology; D003875:Drug Eruptions / Q000175:diagnosis* / Q000209:etiology; D006801:Humans; D010328:Patch Tests / Q000379:methods*; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D013997:Time Factors
chemical_list: D000305:Adrenal Cortex Hormones