An optimal method for experimental provocation of polymorphic light eruption.
BACKGROUND
There is controversy about the best method to induce polymorphic light eruption (PLE) experimentally. Objectives To review articles on PLE induction and design a UV radiation protocol that improves success rates with clinically relevant doses of environmentally relevant solar-simulated radiation (SSR).


METHODS
All articles on the experimental provocation of PLE published since 1980 were reviewed. Photoprovocation of lesions was studied in 25 PLE patients. The 24-hour minimal erythemal dose (MED) of SSR was determined. Thereafter, six 4 x 4-cm adjacent sites on previously affected and previously unaffected skin were exposed to 0.25, 0.5, 0.75, 1.0, 1.25, 1.5 MED of SSR for 3 to 4 consecutive days. The study periodwas autumn to spring in London, England (51 degrees north latitude).


METHODS
Relationship between PLE induction and biological and physical exposure parameters.


CONCLUSIONS
The review shows that fractionated erythemally effective UV-A exposures were more successful than single-sunburning UV-B doses. Photoprovocation of PLE was successful in 68% of patients after 2 to 3 SSR exposures that were not necessarily erythemal. There was no difference in success rate between previously affected and previously unaffected skin. Our data indicate that PLE is more likely to be induced when the natural causes of the disease are simulated.
van de Pas
Chantalle B
CB
St John's Institute of Dermatology, Guy's, King's, and St Thomas' School of Medicine, King's College London, England.
Hawk
John L
JL
Young
Antony R
AR
Walker
Susan L
SL
D002986:Clinical Trials as Topic; D006801:Humans; D010787:Photosensitivity Disorders / Q000175:diagnosis*; D011237:Predictive Value of Tests; D011829:Radiation Dosage; D012867:Skin / Q000528:radiation effects; D012882:Skin Tests / Q000592:standards*; D014466:Ultraviolet Rays