Fotoallergiline

Fotoallergiline is a term used to describe an allergic reaction that is triggered or exacerbated by exposure to light, particularly ultraviolet (UV) radiation. It is a type of photosensitivity disorder. This reaction occurs when a substance, either a medication or a chemical applied to the skin, absorbs UV light and undergoes a chemical change. This altered substance then becomes recognized by the immune system as foreign, leading to an allergic response.

There are two main types of photoallergic reactions: photoallergic contact dermatitis and photoallergic drug reactions. Photoallergic contact dermatitis is caused by topical substances like sunscreens, fragrances, or certain medications applied directly to the skin. When exposed to sunlight, these substances become allergenic and cause a rash, itching, and inflammation at the site of contact. Photoallergic drug reactions occur when systemic medications, such as certain antibiotics or diuretics, cause photosensitivity. In this case, the reaction can appear on sun-exposed areas of the skin, even if the medication was not applied topically.

Symptoms of fotoallergiline typically include redness, itching, swelling, and sometimes blistering of the skin in areas exposed to sunlight. The reaction usually appears 24 to 72 hours after exposure to both the causative agent and UV light. Diagnosis often involves a thorough medical history, examination of the rash, and sometimes photopatch testing, where the suspected substance is applied to the skin and then exposed to UV light to reproduce the reaction. Management focuses on identifying and avoiding the causative agent and protecting the skin from further sun exposure.