[en] Photodermatoses are a skin disease caused by an increased sensitivity of the skin towards the sunlight. We divide them into 4 main categories: 1) immunologically mediated photo dermatosis, that are polymorphic light eruption, actinic prurigo, hydroa vacciniforme, solar urticaria and chronic actinic dermatitis, 2) drug-induced and chemically-induced photosensitivity, that includes phototoxic and fotoallergic reactions, porphyria, 3) photo aggravated conditions, 4) defective DNA repairs disorders. Over a very wide range of diseases, their therapy is similar, it means strict photo protection against UVB and UVA radiation and appropriate clothing. (author)