Sun Allergy (Polymorphic Light Eruption): Causes and Relief
An itchy rash on the arms, neck or chest after sun exposure is often polymorphic light eruption, a common sun allergy. Learn triggers, relief and prevention.
Condition guide
Sun allergy (polymorphic light eruption)
Also known as Polymorphic light eruption, PMLE, Polymorphous light eruption, Sun rash, Rash after sun exposure.
In short
An itchy rash that appears a few hours to a couple of days after time in the sun, usually on the arms, the V of the neck, the chest or the legs, is most often polymorphic light eruption (PMLE), the most common rash caused by ultraviolet light. It is mostly triggered by UVA, which passes through window glass, and is more common in spring and early summer. It usually settles within about a week if you stay out of strong sun, and flares can often be prevented with gradual sun exposure, covering clothes and a broad spectrum sunscreen.
Typical signs
- An itchy or burning rash a few hours to a few days after sun exposure
- Small raised spots or blisters, or larger blotchy areas
- On brown skin, often a pinpoint rash of tiny bumps
- The forearms, backs of the hands, V of the neck, upper chest and legs, with the face often less affected
- Flares in the first hot weeks of summer, after a hill or beach trip, or after long journeys by a sunny window
When to see a dermatologist
- The rash is getting worse or has not improved after one week
- The rash is very swollen, blistered or widespread
- You also have joint or muscle pain, extreme tiredness or a fever
- The rash appears on the face every time you step outside
- It started after a new medicine or skin product
- You keep getting dark patches after each flare
Signs vary from person to person and several skin conditions look alike. Only an examination can confirm a diagnosis.
Read the guides
Full, referenced articles on sun allergy (polymorphic light eruption) written for Indian skin, with answers to common questions.
Worried about sun allergy (polymorphic light eruption)?
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This page is a short summary for general education and does not replace a consultation with a qualified dermatologist. Do not start, stop or change any medicine based on this page. Read the full medical disclaimer.