title: Clinical and experimental studies of octocrylene's allergenic potency.
abstract: BACKGROUND
  Reports of positive patch test and photopatch test reactions to the chemical ultraviolet filter octocrylene have increased during the last decade. Little is known about the reason for octocrylene's allergenic activity.
  
  
  OBJECTIVE
  To present and discuss the results of patch tests and photopatch tests with octocrylene, and to investigate the possible cause of its allergenic properties.
  
  
  METHODS
  Results of patch tests and photopatch tests with octocrylene in patients with adverse skin reactions to sunscreen products and/or ketoprofen were collected. The allergenic potency of octocrylene was investigated in the murine local lymph node assay (LLNA). Chemical reactivity assays were used to mimic octocrylene's interaction with biomolecules.
  
  
  RESULTS
  We report 23 cases of positive test reactions to octocrylene (5 patch test and 18 photopatch). Notably, many of these patients also had positive photopatch test reactions to ketoprofen and benzophenone-3. Octocrylene was shown to be a moderate sensitizer in the LLNA, and it reacted with amines such as lysine, but not with thiols such as cysteine.
  
  
  CONCLUSIONS
  The clinical studies show that octocrylene is both a photocontact allergen and a contact allergen. Octocrylene's ability to cause contact allergy is probably attributable to its reactivity towards lysine. To be able to understand why octocrylene causes photocontact allergy, further studies are needed.
authors.affiliation: Dermatochemistry and Skin Allergy, Department of Chemistry, University of Gothenburg, SE-412 96, Gothenburg, Sweden.
authors.forename: Isabella
authors.initials: I
authors.lastname: Karlsson
authors.forename: Katrien
authors.initials: K
authors.lastname: Vanden Broecke
authors.forename: Jerker
authors.initials: J
authors.lastname: Mårtensson
authors.forename: An
authors.initials: A
authors.lastname: Goossens
authors.forename: Anna
authors.initials: A
authors.lastname: Börje
mesh_terms: D000179:Acrylates / Q000009:adverse effects* / Q000378:metabolism; D000328:Adult; D000368:Aged; D000818:Animals; D001577:Benzophenones / Q000009:adverse effects; D002648:Child; D002675:Child, Preschool; D017449:Dermatitis, Allergic Contact / Q000209:etiology*; D017454:Dermatitis, Photoallergic / Q000209:etiology; D005260:Female; D006801:Humans; D007660:Ketoprofen / Q000009:adverse effects; D023441:Local Lymph Node Assay; D008239:Lysine / Q000378:metabolism; D008297:Male; D051379:Mice; D008875:Middle Aged; D010328:Patch Tests / Q000379:methods; D012867:Skin / Q000378:metabolism; D013473:Sunscreening Agents / Q000009:adverse effects*; D055815:Young Adult
chemical_list: D000179:Acrylates; D001577:Benzophenones; D013473:Sunscreening Agents; C088673:octocrylene; D007660:Ketoprofen; C005290:oxybenzone; D008239:Lysine