Polymorphic light eruption

What does the rash look like?

The rash can take many different forms (known as being "polymorphic"):

most people getcrops of 2-5mm pink or red raised spots
some people get blisters that turn into larger, dry red patches (looks a bit like eczema )
less commonly, the skin patches look like targets or bulls-eyes, a bit like theskin rash erythema multiforme

It can be easy to mistake polymorphic light eruption for prickly heat . Prickly heat is caused by warm weather or overheating, rather than sunlight or UV light. The skin in prickly heat doesn't "harden" or desensitise, as it can do in polymorphic light eruption (see information on desensitisation below).

Medically Reviewed by a doctor on 21 Dec 2018

Articles for polymorphic light eruption

Introduction

Polymorphic light eruption is a fairly common skin rash triggered by exposure to sunlight or artificial ultraviolet light. It lasts for up to two weeks, healing without scarring.

What does the rash look like?

The rash can take many different forms (known as being "polymorphic"): most people getcrops of 2-5mm pink or red raised spots some people get blisters that turn into larger, dry red patches (looks

How big a problem is it?

The skin rash may be a rare occurrence, or may happen every time the skin is exposed to sunlight. It ranges from mild to severe. Sometimes, as little as 30 minutes of sun exposure is enough to cause

Who's affected?

Polymorphic light eruption is more common in women than men. It particularly affects those who are fair, although it can affect those with dark skin. It usually starts from the ages of 20 to 40, alth

What is the cause?

Polymorphic light eruption is thought to be caused by UV light altering a substance in the skin, which the immune system then reacts to, resulting in the skin becoming inflamed. Polymorphic light eru

How is it treated?

There's no cure for polymorphic light eruption, but careful avoidance of the sun and using sunscreens will help you manage the rash. Generally, avoid the sun between 11am and 3pm, and wear protective

What's the outlook?

Many people with polymorphic light eruption find the skin complaint improves over years the skin may harden (become more resistant to sunlight) during the summer, which means more and more sun can be

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