Polymorphous Light Eruption Clinical Presentation

Updated: Jan 22, 2020
  • Author: Saud A Alobaida, MBBS, FRCPC; Chief Editor: Dirk M Elston, MD  more...
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Presentation

History

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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Physical Examination

As the name implies, clinical manifestations of polymorphous light eruption (PMLE) vary. Many different morphologies may appear on sun-exposed areas, but usually only one morphology dominates in a given individual.

Papules (most common), plaques, papulovesicles, and eczematous and erythema multiforme–like lesions are the most common morphologies. Photosensitive erythema multiforme and erythema multiforme–like PMLE can be difficult to distinguish clinically. Combined morphological types of lesions, while uncommon, do occur. For example, the small papular variety may coalesce to form an eczematous type and large papular lesions may produce plaques or assume an annular configuration. Note the images below.

Polymorphous light eruption on the chest. Courtesy Polymorphous light eruption on the chest. Courtesy of DermNet New Zealand (http://www.dermnetnz.org/assets/Uploads/_resampled/FitWzY0MCw0ODBd/WatermarkedWyIyNTg0MCJd/pmle-15.JPG).
Polymorphous light eruption on the chest. Courtesy Polymorphous light eruption on the chest. Courtesy of DermNet New Zealand (http://www.dermnetnz.org/assets/Uploads/_resampled/FitWzY0MCw0ODBd/WatermarkedWyIyNTg0MSJd/pmle-14.jpg).
Polymorphous light eruption on the arm. Courtesy o Polymorphous light eruption on the arm. Courtesy of Waikato District Health Board and DermNet New Zealand (http://www.dermnetnz.org/assets/Uploads/_resampled/FitWzY0MCw0ODBd/WatermarkedWyIyNTg0MCJd/pmle-22.JPG).
Polymorphous light eruption on the thighs and hand Polymorphous light eruption on the thighs and hand. Courtesy of DermNet New Zealand (http://www.dermnetnz.org/assets/Uploads/reactions/pmle2.jpg).

Sun-exposed skin, especially that normally covered in winter (eg, upper chest, arms), is affected primarily, but autosensitization may lead to a generalized involvement.

Cheilitis is uncommon in patients in the United States. In such patients, the rare diagnosis of actinic prurigo (AP) is a more likely cause of the inflammatory photosensitivity disorder. Cheilitis is more common in the tropics and might be the only manifestation of the PMLE. In the case of photosensitive cheilitis, PMLE must be distinguished from chronic actinic cheilitis and the eczematous cheilitis produced by photosensitizing agents.

Other variants of PMLE include a pinpoint papular variant observed in African Americans, benign summer light eruption (BSLE), solar purpura, juvenile spring eruption (JSE), localized PMLE, scar PMLE, and PMLE sine eruption.

The pinpoint variant seems to be observed in patients with Fitzpatrick skin types IV-VI. [30] African Americans present with pinpoint papules (1-2 mm) that can be observed on sun-exposed areas, sparing the face and flexural surfaces. [37] It has also been described in a series from Singapore [38] and in a series of 34 Taiwanese patients whose rash resolved with sun protection. [29] Ten of these Taiwanese patients had mild spongiosis on biopsy.

BSLE presents with a mild form.

JSE presents in children, with papules or papulovesicles that can erode and typically involve the helices of the ears. JSE is more common in boys than in girls, likely because girls traditionally have longer hair that protects their ears from sunlight exposure.

PMLE sin eruption presents with no visible lesions but symptoms of pain or pruritus upon exposure to UV light.

In a retrospective study from Spain in 2013, [39] 5 men and 4 women were suggested to have a localized variant of PMLE, termed ”spring and summer eruption of the elbows" by the authors. The mechanism that confined the lesions to these specific areas was not determined.

Scar PMLE that can occur on hypopigmented scars has been noted in India. [40]

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