Polymorphous light eruption
| Polymorphous light eruption | |
|---|---|
| Classification and external resources | |
| Specialty | dermatology |
| ICD-10 | L56.4 |
| ICD-9-CM | 692.72 |
| DiseasesDB | 10327 |
| MedlinePlus | 001477 |
| eMedicine | derm/342 |
Polymorphous light eruption (PLE), or polymorphic light eruption (PMLE), is a skin condition triggered by sunlight.
Two subtypes have been described:
Photosensitivity is also found in some of the Porphyrias. Nearly all cases of Porphyria cutanea tarda exhibit blister formation on the skin within 2–4 days of light exposure. Variegate porphyria and Hereditary coproporphyria can also exhibit symptoms of light induced blisters.
Symptoms include skin irritations, which may be itchy or painful, and are sometimes confused with hives. These irritations appear upon or shortly after exposure to sunlight, and may last from 1 to 7 days. Lesions have been photographed showing fluid-filled blisters.
Secondary symptoms include flu-like symptoms; body aches, skin sensitivity, muscle aches, fever, dizziness, exhaustion, vision impairment, and disorientation.
The cause of PLE is not yet understood. It is thought to be due to a type IV delayed-type hypersensitivity to an allergen produced in the body following sunlight exposure. It can be provoked by UVA or UVB rays. Some progression to autoimmune disease has been observed.
In cases of cutaneous Porphyria alcohol consumption has been found to be a strong trigger. Consumption of alcohol inhibits certain portions of Porphyrin synthesis which creates the excess enzymatic intermediaries. These compounds, upon circulation in the blood stream and oxidized by light are responsible for the itchy blisters and plaques.
Generally, PLE resolves without treatment; also, PLE irritations generally leave no scar. However, in severe cases the use of steroids is necessary to help reduce inflammation and increase quality of life of the patient. There are also other therapies for patients who are severely impacted, such as light therapy to harden the skin's surface.
The cases of this condition are most common between the spring and autumn months in the northern hemisphere.
Typically, 5-20% of fair skinned populations are affected, but it can occur in any skin type. It is more common in females than in males. The condition can affect all ethnic groups and research suggests that 20% of patients have a family history of the complaint. Those suffering from PLE usually do so by age 30.
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