An Optimal Method for Experimental Provocation of Polymorphic Light Eruption

Immunologically Mediated Photodermatoses

“…The test results are read immediately after the UV exposure, up to Table II. Photodiagnostics in immunologically mediated photodermatoses Characteristic PLE [2,12,15,16,18,43] Hydroa vacciniforme [2,12,28] Solar urticaria [2,12,38] Actinic prurigo [2,12,24] Chronic actinic dermatitis [2,12,32] Action spectrum UVA ++ (up to 75%) UVB + test area UV non-exposed, healthy skin (5 · 5 cm test site)…”

“…Therefore, knowledge of the action spectra is significant in the diagnosis and prevention of IMP. [1,2,[12][13][14][15] However, diagnosing photosensitive disorders also depends on clinical experience and meticulous attention to detail in taking the patient history, since patients may not attribute symptoms to UV exposure. The pattern of the reaction may suggest the possibility of photosensitivity.…”

Susceptibility to UV-A and UV-B Provocation Does Not Correlate With Disease Severity of Polymorphic Light Eruption

“…Positive photoprovocation in patients with PLE has varied among reported studies between 0% and 100% during the last 20 years. [9][10][11][12][16][17][18][19][20][21] This large variation can be attributed to differences in UV source used, number and total dose of exposures, and possibly some patient characteristics. Our data confirm that UV-A lamps give the highest number of positive responses and are therefore the most suitable sources for confirming the disease.…”

Validation of the ‘Polymorphic Light Eruption Severity Index’

“…Successful experimental provocation of the eruption by ultraviolet (UV) radiation usually requires repeated exposures; the ease of provocation by such exposures can be regarded, not unreasonably, as a reflection of disease severity in a patient. Reflecting this, attempts to provoke PLE have had variable success rates (0–100%, reviewed by van de Pas et al 7 ), partly because of variations in disease severity between patient cohorts. However, success rates also vary due to seasonal variation, 8 and to large variations in provocation protocols between centres.…”

“…Patients received one of two provocation protocols, for reasons not affecting the current report. Seventeen subjects were participating in a pilot study using a range of doses (protocol A) to determine an optimal provocation method, the results of which have been previously described, 7 and the PLESI scores of nine of these were published 4 . Briefly, these 17 patients were exposed to 0·25, 0·5, 0·75, 1·0, 1·25 and 1·5 multiples of the buttock MED at 24‐h intervals on three occasions, on the buttock and either the arm or back.…”