What is a polymorphic light eruption?
Polymorphic light eruption (PMLE) is a rash which comes on after being in strong sunlight.
- It looks like reddened skin with raised red spots or small blisters.
- It is generally itchy and uncomfortable.
- It can feel sore or burning.
- It occurs most often on areas of skin that haven't seen the sun for a while - it is more common on the arms and the chest than on the face or the hands.
- It can take as little as 20 minutes of strong sun to trigger the rash. The rash generally comes on within a few hours of going into the sun.
- The rash usually gets better within a few days.
- The rash heals completely, without scarring.
The rash can look quite different in different people, although in any one person it usually looks the same each time it comes. It can range from mild to severe.
The rash generally clears up within a week if you stay out of the sun. However, if you get more sunshine on your skin then it is likely to get worse. The rash may come back if you go into strong sun again. However, symptoms tend to improve during the summer, as your skin becomes more adapted to sunlight.
Some people have a more severe form of PMLE which can even occur in winter or under fluorescent lights.
What is the outlook for polymorphic light eruption?
Although no treatment gets rid of polymorphic light eruption (PMLE) for ever, the outlook is good. The rash heals completely, although while it lasts it may be uncomfortable or unsightly.
In the longer term:
- For most people, PMLE tends to follow a pattern and it usually comes back each year when you first get exposed to strong sunshine. Over time you learn how much sun your skin can tolerate and you should try to keep within that limit to avoid PMLE. You will learn to introduce your skin to sunlight gradually in the spring.
- For some people, PMLE may improve or clear up completely over the years.
- PMLE also tends to improve for women after the menopause (when menstrual cycles stop at around the age of 50).
Did you find this information useful?
- Polymorphic Light Eruption; DermNet NZ
- Fesq H, Ring J, Abeck D; Management of polymorphous light eruption : clinical course, pathogenesis, diagnosis and intervention. Am J Clin Dermatol. 2003 4(6):399-406.
- Percy Lehmann P and Schwarz T; Photodermatoses: Diagnosis and Treatment, Dtsch Arztebl Int. 2011 March 108(9): 135–141
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