Polymorphous Light Eruption

What is Polymorphous Light Eruption?

Resulting from exposure to the sun, Polymorphous Light Eruption is a skin rash that’s considered harmless. PMLE usually occurs due to excessive sun exposure or when getting back into the habit of going outdoors after the winter season. It differs from sunburn, although it can also cause itching and slight discomfort. It’s often temporary and usually goes away fairly quickly.

Causes of PMLE

PMLE is caused by exposure to UV (ultraviolet) and visible light. It can result from direct or indirect exposure to sunlight, as from sitting near a sun-exposed window. It may also be caused by exposure to fluorescent lighting. PMLE may be affected by individual immune system reactions, explaining why some people develop the rash and others are unaffected.

What are the Symptoms of Polymorphous Light Eruption?

  • Visible rash (skin discoloration)
  • Small, raised spots
  • Small blisters
  • Itching or a burning sensation

How is Polymorphous Light Eruption Treated?

Diagnosis involves visual examination of the rash and may include blood tests or a biopsy to rule out skin cancer or other conditions. PMLE is sometimes confirmed through photo-testing where a small patch of skin is exposed to artificial light to see how it reacts. Symptoms of PMLE often go away after making an effort to minimize sun exposure or when skin becomes accustomed to regular sunlight again.

Treatment may include:

  • Hydro-cortisone cream
  • Corticosteroids
  • Topical ointments
  • Antihistamine tablets (to minimize itching)

Polymorphic light eruption is not an indication of skin cancer and is not contagious. It usually recurs in the same pattern. More common in women and younger adults, PMLE tends to appear on people who live in temperate areas that aren’t excessively hot or cold. Risk of developing PMLE can be reduced by wearing sunscreen with an appropriate SPF level and staying indoors during times when sunlight is strongest.

Last Reviewed:
September 21, 2016
Last Updated:
August 29, 2017
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