Photocontact Dermatitis

Abstract

Photocontact dermatitis (PCD) belongs to the category of skin diseases known as photodermatoses, which are skin disorders caused or aggravated by ultraviolet (UV) radiation and/or visible light. PCD is divided into two categories: Phototoxic and photoallergic. Phototoxic (photo-irritant) reactions are caused by direct damage to tissue resulting from light activation of the photosensitizing agent without an immunological basis. On the other hand, photoallergic reactions are cell-mediated immune responses in which the antigen is the light-activated photosensitizing agent and these reactions only occur after previous specific sensitization. PCD can be caused by either cutaneous contact or systemic uptake [1]. Chronic actinic dermatitis, a condition which is clinically similar to photodermatitis, can occur both as a sequelae of photoallergic reactions or de novo [2].