photodermatosis

Photodermatosis refers to a group of skin conditions characterized by abnormal reactions to sunlight or artificial ultraviolet (UV) radiation. These conditions can result in erythema, eruptions, or other skin changes upon exposure to sunlight, often with no prior skin pathology.

Photodermatoses are classified into endogenous and exogenous types. Endogenous photodermatoses are caused by intrinsic factors, such as autoimmune responses, while exogenous types are triggered by external agents, including medications or chemicals that increase photosensitivity.

Common types of photodermatosis include polymorphic light eruption, actinic dermatitis, and solar urticaria. Polymorphic light eruption is the most prevalent and presents as itchy, erythematous, and sometimes papular or vesicular eruptions on sun-exposed skin. Actinic dermatitis involves chronic or recurrent eczema-like lesions, often in fair-skinned individuals. Solar urticaria manifests as rapid-onset hives after sun exposure.

Diagnosis involves a detailed patient history, clinical examination, and phototesting to determine the wavelength-specific photosensitivity. Patch testing or photopatch testing may be used to identify contact allergens or photoallergens contributing to the condition.

Management primarily involves strict sun avoidance, use of broad-spectrum sunscreens, and protective clothing. Pharmacologic treatments include antihistamines, topical corticosteroids, and immunosuppressive agents in severe cases. Phototherapy and desensitization procedures may be considered under specialist supervision for certain conditions.

The prognosis varies depending on the type and severity of photodermatosis. Early diagnosis and appropriate management can significantly reduce symptoms and improve quality of life.