Polymorphous Light Eruption: Causes, Symptoms, and Treatment
Written by Sumiran Racherla, MD. Medically reviewed by Harsha Moole, MD, Internal Medicine. Last reviewed: October 23, 2026.
What kind of doctor treats Polymorphous Light Eruption?
A dermatologist, a doctor who treats skin conditions, usually diagnoses and treats polymorphous light eruption. Your regular doctor may be able to treat it first and can refer you to a dermatologist. A direct primary care or concierge doctor can be a first stop for an evaluation and can refer you to a specialist when needed.
What is polymorphous light eruption?
Polymorphous light eruption is a skin rash that can happen after being in the sun. It is also called polymorphic light eruption, or PLE. It usually goes away on its own if you stay out of the sun, but it can keep coming back.
The word polymorphic means many shapes. The rash can look like small red bumps, larger red areas, or blisters. PLE is the most common rash caused by ultraviolet (UV) light, the part of sunlight that can harm skin. It is not infectious, so it does not spread from person to person.
Symptoms
The main symptom is a rash. It usually shows up within a few hours or days of being in the sun. The rash may:
- Have small raised spots or blisters.
- Have larger blotchy areas.
- Be itchy or feel like it is burning.
- Be red or pink. This may be harder to see on brown or black skin.
The rash can appear anywhere on the body. It is often on places that are not regularly in the sun, such as the arms, legs, or chest. A similar rash on the ears is called juvenile spring eruption. PLE can look like heat rash, also called prickly heat.
Causes and who gets it
PLE is a reaction to sunlight. Doctors do not know exactly why it happens. It might be linked to the immune system, the body's defense system. Sunlight, even after passing through window glass, can set it off. As little as 20 minutes of sun can trigger the rash.
It is more likely when your skin gets strong sun for the first time in a while. This can be in spring or early summer, or on a trip to a sunny country. As summer goes on, your skin gets used to the sun, and the rash is less likely.
You are more likely to get PLE if you are under 40, are a woman, or have white skin. It can affect people of all skin types. About 15 percent of people with PLE know of other family members who have it.
How doctors diagnose it
A dermatologist bases the diagnosis on how the rash looks and on a history of the rash after sun. If there is any doubt, tests can rule out other conditions that cause sun sensitivity. Sometimes doctors use photo-testing. This means testing the skin with different kinds of light to see if the rash appears.
Treatment
PLE usually does not need treatment. No medicine can cure it. The aim is to ease symptoms and keep the rash from coming back. These steps can help:
- Stay out of the sun, especially between 11am and 3pm, when the sun is strongest.
- Use sunscreen with a sun protection factor (SPF) of 50 or more. Wear a sun hat and protective clothing.
- Put sunscreen on 15 to 30 minutes before going out, and reapply it every 2 hours and after swimming.
- Take antihistamines, medicines that ease itching, if the rash is itchy.
- Use calamine lotion or emollients, which are moisturizing creams, to keep the rash cool.
If symptoms get worse, doctors may use steroid tablets or steroid creams, antihistamines, or phototherapy, which is light therapy. For very troublesome cases, doctors may try desensitisation. This slowly raises skin resistance with growing doses of UV light in early spring. It has to be repeated every spring. People who avoid the sun a lot may be at risk of low vitamin D, so they should think about checking their levels.
When to see a doctor
See a doctor if the rash is getting worse or has not gotten better after 1 week. See a doctor too if the rash is swollen, or if you also have joint and muscle pain or extreme tiredness. A pharmacist can also suggest emollients and antihistamines.
How a direct primary care or concierge doctor fits in
A direct primary care doctor charges a flat monthly fee instead of billing insurance, while a concierge doctor usually charges more and often works alongside insurance. Either type can look at the rash, talk through sun safety, and refer you to a dermatologist if the rash is severe or keeps coming back.
Common questions
Is polymorphous light eruption contagious?
No, polymorphous light eruption is not infectious, so it does not spread from person to person. It also has no connection with skin cancer.
How long does the rash last?
The rash usually goes away in around 1 week if you stay out of the sun. It can last longer or get worse if you keep going in the sun. It may also come back when your skin sees sunlight again.
Can polymorphous light eruption be cured?
No medicine can cure it, but many people do not get it again if they avoid strong sun and use a good sunscreen. The tendency to get PLE may go away on its own after a few years as the skin gets used to sunlight.
Can it happen through a window?
Yes, the rash can appear even when sunlight has passed through window glass. As little as 20 minutes of sun can set it off.
Sources
- NHS - Polymorphic light eruption
- British Association of Dermatologists - Polymorphic light eruption
- MedlinePlus - Polymorphic light eruption on the arm
Medical Disclaimer
This content is for general educational and informational purposes only and is not medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment, and reading it does not create a doctor-patient relationship. Always seek the advice of your physician or another qualified health provider with any questions about a medical condition, and never disregard or delay seeking professional advice because of something you read here. If you think you may have a medical emergency, call 911 (or your local emergency number) immediately.
