Polymorphic solar dermatitis is an eruption triggered by the sun's rays . It can appear at any age, but most commonly occurs in people with very light skin, especially women.
Causes
Polymorphic solar dermatitis represents an unusual reaction due to the release of some chemical mediators in the skin responsible for itching, following exposure to ultraviolet radiation . This triggers an inflammation, which is evident in the skin. The exact etiology is unknown, however the disorder does not appear to be related to any systemic disease, nor to any drug.
How it manifests itself
Solar polymorphic dermatitis causes various cutaneous manifestations: from erythematous and itchy papules to plaques, from vesicles to pustules . The eruptions appear on the most photo-exposed areas (face, neck, décolleté and arms), especially in spring-summer . Usually, polymorphic solar dermatitis occurs a few hours after the start of sun exposure.
How to intervene
The best therapy is to moderate sun exposure : by doing so, itching and other skin manifestations self-limit and improve spontaneously within a few days. To alleviate the symptoms, then, the dermatologist can prescribe antihistamines and corticosteroid drugs.
The gradual exposure to UV light - using PUVA phototherapy or treatment with narrow band UVB (312 nm) - can lead to greater tolerance to sunlight.
