Fotodermatoos

Fotodermatoos is a general term used to describe any adverse skin reaction that is provoked by light. These reactions can be triggered by ultraviolet (UV) radiation, visible light, or even infrared radiation, and they can manifest in various ways. The underlying cause can be an intrinsic photosensitivity, where the skin has an abnormal reaction to light due to an underlying medical condition, or an extrinsic photosensitivity, caused by the application of a photosensitizing agent to the skin, such as certain medications or chemicals.

The clinical presentation of fotodermatoos is diverse. Common forms include photoallergic reactions, which are immune-mediated and develop after repeated sun exposure, and phototoxic reactions, which are non-immune and occur when a photosensitizing substance absorbs light energy and releases it in a way that damages skin cells. Symptoms can range from itching, redness, and swelling to blistering and eczema-like rashes. The severity and appearance of the reaction often depend on the individual's susceptibility, the duration and intensity of light exposure, and the concentration of the photosensitizing agent if present. Diagnosis typically involves a thorough medical history, physical examination, and sometimes phototesting, where the skin is exposed to specific wavelengths of light under controlled conditions to identify the causative agent or trigger. Management focuses on avoiding light exposure, using broad-spectrum sunscreens, and treating the inflammatory symptoms with topical or oral medications.