Discovery - University of Dundee - Online Publications

Library & Learning Centre

Can a positive photopatch test be elicited by subclinical irritancy or allergy plus suberythemal UV exposure?

Can a positive photopatch test be elicited by subclinical irritancy or allergy plus suberythemal UV exposure?

Research output: Contribution to journalArticle

View graph of relations

Authors

  • P. E. Beattie
  • N. J. Traynor
  • J. A. Woods
  • R. S. Dawe
  • J. Ferguson
  • S. H. Ibbotson

Research units

Info

Original languageEnglish
Pages235-240
Number of pages6
JournalContact Dermatitis
Journal publication dateNov 2004
Volume51
Issue5-6
DOIs
StatePublished

Abstract

Photopatch test (PhPT) interpretation is difficult and clinical relevance is not always apparent. A positive PhPT may reflect photocontact allergy or phototoxicity. We hypothesized that it may also reflect the additive or synergistic effects of a suberythemal reaction to a contact irritant [e.g. sodium lauryl sulfate (SLS)] or allergen (e.g. nickel) and suberythemal UV exposure. 10 nickel allergic volunteers had duplicate SLS and nickel series applied on either side of the back for 24 h and 48 h, respectively. After removal, one side was irradiated with 5 J/cm(2) UVA or the dose below the minimal erythema dose for solar-simulated radiation (SSR). The minimal irritancy dose (MID) for SLS and the minimal allergenic dose (MAD) for nickel were determined visually and objectively by erythema meter. While photoaugmentation of subclinical contact allergy or irritancy occurred in some subjects, photosuppression occurred in roughly an equal number. UVA changed the nickel MAD at 48 h in 2 of 5 volunteers but not the SLS MID. SSR changed the nickel MAD in 4 of 5 and the SLS MID in 3 of 5. 2 subjects (none after UVA) showed erythema only in the irradiated set of patches, which could have been interpreted as a positive PhPT. We have demonstrated photoaugmentation and photosuppression of contact allergy and irritancy, which could result in false-positive or false-negative interpretation of PhPTs.

Documents

Library & Learning Centre

Contact | Accessibility | Policy