Polymorphous light eruption (PMLE) is a common skin reaction in people who are sensitive to sunlight (ultraviolet light).
The exact cause of PMLE is unknown. However, it may be genetic. Doctors think it is a type of delayed allergic reaction. It is common among young women who live in moderate (temperate) climates.
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:
The health care provider will examine your skin. Usually, the provider can diagnose PMLE based on your description of the symptoms.
Tests that may be done include:
Steroid creams or ointments containing vitamin D may be prescribed by your provider. They are used 2 or 3 times a day at the start of the eruption. 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.
Many people become less sensitive to sunlight over time.
Call for an appointment with your provider if PMLE symptoms do not respond to treatments.
Protecting your skin from the sun can help prevent PMLE symptoms:
Reviewed By: Michael Lehrer, MD, Clinical Associate Professor, Department of Dermatology, University of Pennsylvania Medical Center, Philadelphia, PA. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.