Photoallergic skin reactions are less common than phototoxic eruptions. However, they can appear due to the systemic application of several drugs. These eruptions are due to delayed cell mediated reactions, on the basis of hapten formation by Langerhans cells, T-cells and later on by various cytokines and chemokines. They usually develop as a consequence of the exposition to solar radiation under the influence of different types of systemic treatment by the samé mechanism which occurs in non-photosensitive allergic contact dermati-tis. Action spectrum of these reactions lies mostly within the range of UVA and UVB ultraviolet radiation (280400 nm), partly also of visible light. The drugs that cause photoallergic skin reactions include for the most part nonsteroidal antiinflammatory drugs, fluorochinolons, phenothiazines, thiazides, and sulphonamides. Skin reactions can be diagnosed by their clinical characteristics, histopathology and particularly by photoe-picutaneous tests with their modifications, sometimes also by exposition tests. Treatment of photoallergic skin reactions is usually symptomatic and often only local, with the use of antiinflammatory ointments or corti-costeroids. Nevertheless, in some cases systemic administration of antihistamines or steroids is inevitable. Protective clothing and high-SPF sunscreens are necessary for long-term photoprotection.

        Key words: photodermatoses, UV-radiation, photoallergy, phototesting, phototherapy, photoprotection