Polymorphous light eruption

  • Definition
    • Polymorphous light eruption (PMLE) is a common skin reaction in people who are sensitive to sunlight (ultraviolet light).

  • Alternative Names
    • Polymorphic light eruption; Photodermatosis; PMLE

  • Causes
    • The cause is unknown. Doctors think it is a type of delayed allergic reaction. It is common among young women who live in moderate (temperate) climates.

  • Symptoms
    • Polymorphous means taking on different forms, and eruption means rash. As the name suggests, symptoms of PMLE are rash-like and are different in different people.

      PMLE most often occurs in spring and early summer on areas of the body exposed to the sun.

      Symptoms usually appear within 1 to 4 days after exposure to sunlight. They include any of the following:

      • Small bumps (papules) or blisters
      • Redness or scaling of the skin
      • Itching or burning of the affected skin
      • Swelling, or even blisters (not often seen)
  • Treatment
    • Steroid creams or ointments containing vitamin D may be prescribed by your health care provider. They are used 2 or 3 times a day. Steroid or other types of pills may be used for more severe cases.

      Phototherapy may also be prescribed. Phototherapy is a medical treatment in which your skin is carefully exposed to ultraviolet light. This may help your skin become used to (sensitized to) the sun.

  • Outlook (Prognosis)
    • Many people become less sensitive to sunlight over time.

  • When to Contact a Medical Professional
    • Call for an appointment with your provider if PMLE symptoms do not respond to treatments.

  • Prevention
    • To prevent PMLE symptoms:

      • Avoid sun exposure during hours of peak sun ray intensity.
      • Use sunscreen. Sun protection with broad spectrum sunblock that works against UVA rays is important.
      • Apply generous amounts of sunscreen with a sun protection factor (SPF) of at least 30. Pay special attention to your face, nose, ears, and shoulders.
      • Apply sunscreen 30 minutes before sun exposure so that it has time to penetrate the skin. Re-apply after swimming and every 2 hours while you are outdoors.
      • Wear a sun hat.
      • Wear sunglasses with UV protection.
      • Use a lip balm with sunscreen.
  • References
    • Gruber-Wackernagel A, Burne SN. Polymorphous light eruption: clinic aspects and pathogenesis. Dermatol Clin. 2014;32:315-34. PMID: 24891054

      Morison WL, Richard EG. Polymorphic light eruption. In: Lebwohl MG, Heymann WR, Berth-Jones J, Coulson I, eds. Treatment of Skin Disease: Comprehensive Therapeutic Strategies. 4th ed. Philadelphia, PA: Elsevier Saunders; 2014:chap 189.