Which clinical history findings are characteristic of polymorphous light eruption (PMLE)?

Updated: Jan 22, 2020
  • Author: Saud A Alobaida, MBBS, FRCPC; Chief Editor: Dirk M Elston, MD  more...
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Polymorphous light eruption (PMLE) tends to manifest in the spring and early summer, or in the wintertime involving the face by reflected sunlight off snow. [35] In addition, PMLE is a recurrent condition and patients state they have had the eruption before and that it went away as time passed.

Typically, the lesions of PMLE first erupt after exposure to strong sun following a period of relative photoprotection such as at the onset of a vacation in a sunny place or at a high altitude in early spring. The eruption decreases in severity as the summer progresses.

The onset of the disease is sudden. The accompanying rash is pruritic and, in some instances, painful. To trigger the eruption, it takes 30 minutes to several hours of sun exposure. The rash appears within hours to days of exposure, and it subsides over the next 1-7 days without scarring, although it has been reported to persist for up to 5 weeks. [36] Sun-exposed skin, especially that normally covered in winter (eg, upper chest, arms), is primarily affected, but autosensitization may lead to a generalized involvement. Most patients have associated pruritus, but some patients describe stinging and pain.

Occasionally, patients experience systemic flulike symptoms after sun exposure.

Unless severe and particularly bothersome, many patients do not visit a physician for PMLE rash.

Jansen traced the natural history of chronic PMLE for 10.5 years in 138 people, [34] 85 of whom were female. In 57% of cases, the PMLE happened in a rapid fashion. Lesions often began in a small photoexposed area and extended to a greater area each year. Light sensitivity tended to increase with each subsequent year. In 50% of patients, yearly hardening phenomena occurred. Ocular and oral involvement occurred in 46% and 49% of the patients, respectively. About 66% patients experienced some general symptoms after solar radiation exposure. [34]

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