Polymorphous light eruption, also known as polymorphic light eruption (PMLE), is a common skin reaction to sunlight that commonly occurs in people with fair skin. The skin reacts and forms red bumpy rashes or slightly raised patches of skin. PLE often occurs during spring and early summer. The rashes also goes away on its own without scarring within 10 days. However, those with severe or persistent rashes may need treatment with medication.
The term “eruption” means rash and it usually appears 30 minutes to several hours after exposure to sunlight. The rashes appear on the upper chest, front of the neck, and arms.
Characteristics of the rash include small bumps and blisters, red, raised rough patches, and itching or burning. Rare symptoms include fever, chills, headache, or nausea. These conditions may be the result of an associated sunburn rather than PMLE.
The exact cause of PMLE isn’t clear. The rashes appear in people who have developed sensitivity to components of sunlight, and in particular, UV radiation from the sun or other equipment such as tanning beds or lamps. This type of sensitivity is called photosensitivity.
UV or ultraviolet radiation is a wavelength of sunlight in a range too short for the human eye to see. UV light is divided into two wavelength bands: ultraviolet A and B. Someone who has photosensitivity can react to both types of UV radiation.
Sensitivity to sunlight lessens with repeated exposure in PMLE. Here are some features of PLE that are somewhat predictable:
- An episode is less likely to occur at the first one or two exposures to sunlight after a long period of no exposure.
- Episodes are less likely to occur as summer progresses.
- After each PMLE episode, it can recur each spring or early summer.
- Some people become less sensitive gradually over the years.
WHEN TO SEE A DOCTOR
See a doctor if you have rashes with no obvious cause, such as a known allergy or recent contact with poison ivy. PMLE is similar to rashes caused by other diseases, which are sometimes serious. This needs prompt diagnosis and proper treatment. Get immediate medical attention if your rash is widespread, painful, and accompanied by fever.
POLYMORPHOUS LIGHT ERUPTION TREATMENT
Treatment for PMLE depends on its severity. In some cases, PMLE resolves on its own with no treatment. However, more severe cases may require medications such as:
- Topical steroids
- Topical tacrolimus
- Oral corticosteroids