From the Guidelines
Polymorphous light eruption (PLE) is a common sun-induced skin rash that typically appears as itchy red bumps, small blisters, or plaques on sun-exposed areas of the body, with a high risk of provocation, particularly with the first few PUVA exposures, as reported in the British Journal of Dermatology 1. The condition occurs when a person's skin reacts abnormally to ultraviolet (UV) radiation, usually developing within hours to days after sun exposure.
- Key characteristics of PLE include:
- Itchy red bumps, small blisters, or plaques on sun-exposed areas
- More common in women and people with fair skin
- Typically appears in spring or early summer
- Symptoms may improve as summer progresses due to a natural hardening effect Treatment and management of PLE focus on prevention through sun protection measures, including:
- Broad-spectrum sunscreen (SPF 30+)
- Protective clothing
- Avoiding peak sun hours For mild symptoms, topical corticosteroids like hydrocortisone 1% cream can reduce inflammation, as well as potent topical steroid application after each exposure in UVB phototherapy, as suggested by the British Association of Dermatologists and British Photodermatology Group guidelines 1. More severe cases may require prescription-strength corticosteroids, oral antihistamines for itching, or phototherapy (controlled UV exposure) to desensitize the skin, with a twice-weekly regimen being the standard in the U.K. 1.
- Post-treatment advice generally includes continued natural sunlight exposure, ranging from 2 h weekly to ‘cautious exposure, with sunscreens for extended outdoor stay’ to ‘expose freely to sun’, as reported in the study 1.
From the Research
Definition and Characteristics of Polymorphous Light Eruption
- Polymorphous light eruption (PLE) is the commonest immuno-mediated photodermatosis, occurring after solar or artificial UV-light exposure 2.
- It affects only the sun-exposed areas, with a preference for the V-area of the chest, arms and forearms, legs, upper part of the back, and rarely the face 2.
- The lesions are itching or burning and vary morphologically from erythema to papules, vesico-papules, and occasionally blisters, plaques, sometimes erythema multiforme-like, insect bite-like wheals, and purpura 2.
Clinical Manifestations and Diagnosis
- The clinical manifestations of PLE befall within a few hours to days from light exposure, last a few days, and subside in about a week without sequelae 2.
- Its diagnosis is based on history, morphology, and phototests 2.
- PLE is considered as a delayed hypersensitivity response to newly UV-induced, but still unidentified, antigen(s) 2.
Treatment and Management
- Broad-spectrum sunscreens and antioxidants, photohardening with PUVA or narrow-band UVB, may be beneficial to prevent the disease 2.
- Therapy is based mainly on topical or systemic corticosteroids 2.
- Preventive treatment with broad-spectrum sunscreens and sunscreens containing DNA repair enzymes, as well as natural photohardening with graduate exposure to sunlight in early spring, could be sufficient in milder cases 3.
- Antioxidants and topical calcipotriol are promising approaches for adjuvant prevention 3.
- Phototherapy, mainly with narrow-band UVB rays, is a more appropriate method in severe cases of the disease 3.