The polymorphic phototest reaction

Abstract

One hundred tem patients with polymorphic light eruption (PMLE) and 58 control subjects were tested with an overdose of erythemogenic radiation. A morphologically abnormal phototest reaction was demonstrable in 72% of the patients with PMLE and in 9% of the control subjects. On the average, a dose of 3.8 times the patient's minimal erythemal dose was needed to produce the reaction. The most common findings in positive phototest reaction sites were edema and itching. A medium-pressure mercury lamp was shown to be as effective as a xenon arc lamp in producing the phototest reaction. The time of the reaction varied considerably in different patients, and frequent inspections of test sites were necessary to detect positive phototest reactions. When properly performed and interpreted, phototesting is a valuable diagnostic procedure for PMLE.

Polychromatic phototest as a prognostic tool for polymorphic light eruption

“…With the exception of one case, the phototests remained positive or negative during the course of the disease. Therefore, our results demonstrate that phototesting is a sensitive tool to assess the value of new treatments (22,(24)(25)(26).…”

“…UVB and especially the ''border area'' between UVB (290-320 nm) and UVA2 (320-340 nm) thus seem to play an important role in the genesis of some PLE (18,21). However, these tests have to be interpreted with caution because false-positive phototests have been observed in control subjects (22,23).…”

The erythemal response to ultraviolet radiation in subjects with polymorphic light eruption

“…The only observed morphological change was a 'peau d'orange' appearance at the sites exposed to high doses of radiation of either wavelength. Although this phenomenon has been interpreted as an abnormal vesicular response (Jansen 1982), in our experience it is frequently observed in normal subjects whenever high enough doses of UV radiation are employed. In common with other workers (Tanenbaum et al, 1981) we attribute this appearance to perifollicular oedema and regard it as a normal response.…”

“…Polymorphic light eruption (PLE) is a relatively common idiopathic photodermatosis in which papular or vesicular lesions or both, develop in response to sun exposure, usually during the spring and early months of summer. Photobiological investigations of this disease have been concerned either with determination of the minimal eythema dose (MED) at different wavelengths using an irradiation monochromator (Magnus, t964;Frain-Bell et al, 1973)3 or with artificial provocation ofthe eruption using one or more exposures of fairly high doses (3-5 MEDs) of ultraviolet (UV) radiation from unfiltered mercury arc lamps or xenon lamps (Epstein, 1980;Jansen, 1982), or high doses of UV-A radiation (~ioo J/cm") from filtered metal halide lamps (Holzle et al, 1982).…”

“…However, the MED represents only a single point, the detection threshold, on the UV-dose erythema-response curve. Reports of abnormal erythemal or morphological responses to high doses of UV radiation in PLE (Epstein, 1980;Jansen, 1982) 104 B.L.Diffey and P.M.Earr suggest there may be a difference in the slope of the dose-response curve for UV-induced erythema in subjects with PLE, compared with normal individuals.…”