What is Polymorphic Light Eruption?
Polymorphic Light Eruption (PMLE) is a common skin condition caused by an abnormal reaction to sunlight, specifically ultraviolet (UV) radiation. It usually appears as an itchy rash or bumps on sun-exposed areas of the skin, often after the first significant sun exposure of the season. PMLE is not contagious or life-threatening but can cause discomfort and affect quality of life.
What causes Polymorphic Light Eruption?
PMLE occurs due to an immune system reaction triggered by UV radiation from the sun. The exact cause is not fully understood, but factors include:
- Sensitivity to UV-A and UV-B rays
- Genetic predisposition (family history)
- Changes in the immune system’s response to sunlight
- More common in fair-skinned individuals and women
- Typically develops in spring or early summer when sun exposure increases
What are the symptoms of Polymorphic Light Eruption?
Symptoms typically appear within hours to days after sun exposure and include:
- Itchy red bumps, blisters, or patches on sun-exposed skin such as the arms, chest, and legs
- Rash may vary in appearance (hence “polymorphic”) from small red bumps to larger plaques
- Burning or stinging sensation in affected areas
- Rash usually resolves within days to weeks but may recur with sun exposure
- Rarely, swelling or peeling of the skin
How is Polymorphic Light Eruption diagnosed?
Diagnosis is usually based on clinical history and physical examination:
- Identification of the rash pattern and timing related to sun exposure
- Excluding other sun-related skin conditions such as eczema or lupus
- In some cases, a skin biopsy may be done to confirm the diagnosis
- Phototesting (controlled UV exposure) in specialized centers can help diagnose PMLE
What are the treatment options for Polymorphic Light Eruption?
Treatment focuses on relieving symptoms and preventing future outbreaks:
- Sun protection: Use of broad-spectrum sunscreen, protective clothing, and avoiding peak sun hours
- Topical corticosteroids: To reduce inflammation and itching
- Antihistamines: To help control itching
- Gradual controlled sun exposure: To help the skin adapt and reduce sensitivity over time (under medical advice)
- In severe cases, phototherapy or oral medications like corticosteroids or immunosuppressants may be prescribed
What is the recovery and prognosis for Polymorphic Light Eruption?
- PMLE is a chronic condition but often improves with repeated sun exposure as the skin becomes more tolerant
- Most people experience fewer or less severe outbreaks over time
- The rash usually resolves completely without scarring
- Proper sun protection and treatment help manage symptoms effectively
How can Polymorphic Light Eruption be prevented or managed long-term?
- Consistent use of sunscreen with high SPF and UVA protection
- Wearing protective clothing, hats, and sunglasses when outdoors
- Avoiding sun exposure during peak hours (10 a.m. to 4 p.m.)
- Gradual and controlled sun exposure early in the season to build tolerance
- Consulting a dermatologist for tailored treatment plans if symptoms persist or worsen