Polymorphous light eruption (PMLE)
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Polymorphous light eruption(PMLE) is a skin condition that develops as a rash in response to sun exposure in individuals sensitive to sunlight. Typically characterized by tiny, inflamed bumps or slightly raised skin patches, this reaction is most common during spring and early summer when sunlight exposure peaks. As the summer progresses, occurrences tend to decrease, although the condition often recurs annually.
Also known as polymorphic light eruption, sun allergy, or sun poisoning, the rash generally resolves itself without scarring within ten days. However, those experiencing severe or persistent symptoms may require medication to manage the condition.
Symptoms
Polymorphous light eruption (PMLE) often appears as an itchy rash on sun-exposed areas of the body, characterized by small red bumps, larger red patches, or even blisters. These skin lesions usually develop within hours of sun exposure, though they can sometimes emerge a few days later. Typically, the symptoms of PMLE last for two to three days, but repeated exposure to UV light during this period can extend the duration of the rash.
Rarely, PMLE can also trigger additional symptoms such as fever, headache, and nausea. The rash commonly appears on the chest, neck, arms, and legs, and seldom affects the face. A special form of PMLE, known as juvenile spring eruption, specifically targets the ears of children, predominantly boys, and presents similar dermatological symptoms.
Seek immediate medical care if your rash is widespread, painful, or accompanied by a fever, as these can be signs of a more severe reaction.
Causes
Polymorphous light eruptions (PMLE) occur when individuals sensitive to sunlight, specifically to ultraviolet (UV) radiation, develop a rash. This condition is a form of photosensitivity, where UV rays trigger immune system reactions that cause skin irritation.
- UV radiation: UV radiation, invisible to the human eye, consists of different wavelengths, primarily ultraviolet A (UVA) and ultraviolet B (UVB) that reach Earth. Both types can provoke reactions in photosensitive individuals. Notably, UVB cannot penetrate glass, unlike UVA, which can pass through. Consequently, exposure to sunlight through windows or on skin protected by sunscreen may still trigger a reaction in those with photosensitivity.
- Photosensitivity: In PMLE, sensitivity to sunlight generally diminishes with repeated exposure. Typically, outbreaks occur after the initial one or two sun exposures following an extended period without sunlight, often in the spring or early summer. The condition usually recurs annually after the initial episode. However, over time, some individuals may see a decrease in their sensitivity, resulting in fewer or no annual episodes.
Risk factors
Polymorphous light eruption can affect anyone, however there are a few things that can increase your risk to likely to have the condition.
- Age: individuals in the 20–40 age range.
- Family history: Have a family member with history of the condition.
- Gender: It is common to female than male.
- Location: People who lives in in places that they have minimal sun exposure.
- Medical condition: People who have their skin easily have sunburns.
Diagnosis
Polymorphous light eruption can likely be diagnosed by a healthcare provider based on a physical examination and your responses to questions. Laboratory testing may be recommended by your healthcare provider to confirm a diagnosis or rule out other diseases. Tests might consist of:
- Blood tests: A blood test may be recommended by your healthcare provider to rule out additional medical conditions, such as lupus erythematosus, an autoimmune disease that can also result in a rash after sun exposure.
- Skin biopsy: A biopsy is when your healthcare provider takes a sample of skin from your rash so that it may be tested in a lab.
- Phototesting: A dermatologist, who specializes in skin diseases, may measure the quantity of UVA and UVB radiation that reaches certain parts of your skin in an attempt to replicate the issue. You are said to be photosensitive—sensitive to sunlight—and you could develop polymorphous light eruption or another condition caused by light if your skin reacts to ultraviolet (UV) radiation.
- Other light-induced conditions: It may be necessary for your healthcare provider to rule out other conditions that cause skin responses when exposed to light. Among these requirements are:
- Chemical photosensitivity: Many substances can cause photosensitivity, including medications, medicinal lotions, perfumes, and plant-based items. When this happens, the skin becomes reactive to sunlight after consuming or coming into touch with a certain substance.
- Solar urticaria: A sun-induced allergic reaction known as solar urticaria results in hives, which are elevated, swollen, itchy welts that emerge and then go away on the skin. After being exposed to the sun, the welts may develop a few minutes later and last for several hours. A persistent disorder that can linger for years is solar urticaria.
- Lupus rash: Many body systems are affected by the inflammatory illness known as lupus. On skin exposed to sunlight, such as the face, neck, or upper chest, one sign is the development of a bumpy rash.
Treatment
Prevention and care:
- Avoid sun exposure: Stay out of the sun between 11 a.m. and 3 p.m., when UV rays are strongest. During peak sun intensity hours, schedule indoor activities.
- Sunscreen: Use broad-spectrum sunscreen with an SPF of at least 30. Apply 15 minutes before going outdoors, and reapply every two hours, or more frequently if sweating or swimming.
- Protective clothing: Wear tightly woven clothes covering arms and legs. Opt for a broad-brimmed hat over a cap for better coverage. Clothing with an ultraviolet protection factor (UPF) of 40 to 50 is recommended. Follow care labels on UV-blocking clothes.
- Minimize UV exposure: If planning a sunny vacation, consider a prophylactic oral corticosteroid like prednisone as prescribed by a healthcare provider.
Treatment options:
- Phototherapy: Gradual exposure to UV light may help “harden” the skin, a technique done under medical supervision.
- Medications: For severe cases, options include antihistamines, hydroxychloroquine, immunosuppressants, topical corticosteroids, or tacrolimus.
Symptom relief:
- Anti-Itch creams: Use creams containing at least 1% hydrocortisone.
- Antihistamines: Helpful if itching is severe.
- Cold compresses: Apply cool, damp towels or take cool baths.
- Blisters: Leave blisters intact to avoid infection; cover lightly with gauze if necessary.
- Pain relief: Nonprescription medications can reduce pain and inflammation.
