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What is Polymorphus Light Eruption (PMLE)?
This is a rash that happens after ultraviolet (UV) light exposure, usually from the sun.
This is also called Spring Eruption, referred to as PMLE, sun allergy, and sun poisoning.
It can happen to all skin colors.
What causes Polymorphus Light Eruption (PMLE)?
Exposure to Ultraviolet Light causes this rash.
It is likely due to the immune system’s reaction to the sun.
Some people’s immune systems do not tolerate sun exposure as well as others.
Therefore, the rash may occur when the immune system does not tolerate the sun well.
When the sun intensity changes, the rash is more likely to happen.
It is most likely to happen in spring, early summer, or on a sunny, snowy day.
When going from a lower UV exposure to a higher UV exposure, the skin senses a shocking change and causes the rash.
It can be inherited.
It is more common if family members have had this rash.
People who have had this rash in the past are more likely to have it again in the future.
What are the symptoms of Polymorphus Light Eruption (PMLE)?
This causes a rash that is usually itchy, and may be painful.
It is red, and can be flat or raised.
If it is painful, it may feel like a sting.
It does not cause scarring.
It is usually seen on areas of the body that are not usually exposed during colder months.
Common areas are the upper arms and chest.
The face is the more common area during the winter, due to the sun’s reflection from the snow.
The rash may result within as little as 30 minutes of sun exposure.
It may also take hours of sun exposure to see it.
It can continue for days to weeks.
Rarely, it can last up to 5 weeks.
How is Polymorphus Light Eruption (PMLE) diagnosed?
Your child’s primary healthcare provider will examine your child.
Your child’s primary healthcare provider will ask you questions about the rash.
Usually, a physical exam and talking to you and your child about the rash help to make the diagnosis.
How can I prevent Polymorphus Light Eruption (PMLE)?
Avoid sun exposure during the most intense hours from 10am to 2pm when possible.
Wearing proper sun protection is the most important.
Wear clothes with UV protection built in.
Wear items to cover sun exposed areas like hats, long sleeves, long pants, and gloves.
Mineral (also called physical) sunscreen is the most protective form of sunscreen.
Use an SPF of 30 (using higher has not been shown to be more protective).
Apply sunscreen 30 minutes prior to sun exposure or swimming.
Apply every 2 hours while out in the sun.
How is this treated?
There is not a specific medication for this rash, but your child’s healthcare provider may prescribe a topical or oral steroid to help with comfort.
Keep your child hydrated.
Encourage a variety to fruits and veggies for good nutrition.
Apply moisturizing creams or lotions like petrolatum to keep the skin hydrated.
For itching:
An antihistamine like cetirizine or loratadine may help.
Using aloe vera, diphenhydramine cream, and calamine lotion may help.
Ice can be applied to the area for soothing.
Oatmeal baths can be helpful, or oatmeal-based lotions.
Avoid itching the area.
When to call your healthcare team:
You think your child is reacting to the sun.
Your child has a rash and fever.
Your child complains of pain from the rash.
Your child is refusing fluids.
Your child is getting worse.
You have other questions or concerns.
📚 References
Article written by TT DO. Reviewed by: TT, DO, JW MD, Patient Education Committee.
This content was adapted from https://emedicine.medscape.com/article/1119686-overview, https://my.clevelandclinic.org/health/diseases/17888-polymorphous-light-eruption-pmle
Images from https://dermnetnz.org/images/polymorphic-light-eruption-images, https://link.springer.com/chapter/10.1007/978-3-319-56017-5_10