Praktické lekárnictvo 3/2018
Drug-induced photosensitivity – part I.
Drug-induced photosensitivity refers to the development of an abnormal adverse skin reaction in the predisposed individuals as a result of the combined effects of a particular medicines (photosensitizers) and light rays from the sun, eventually from other light sources. It can occur after systemic and/or topical administration of the drug administered at its usual doses for therapeutic, diagnostic or prophylactic purposes. As the skin absorbs light rays this can cause a chemical change to a medicine that is present in the skin resulting in phototoxicity and/or photoallergy. More common phototoxic reactions result from direct cellular damage caused by light activation of the photosensitising agent, whilst rarer photoallergic reactions are a T-cell mediated immune response in which the hapten or complete antigens the light-activated photosensitising agent. Currently, drug-induced photosensitivity is often poorly diagnosed, so it is necessary to increase the awareness of doctors and health care professionals about this type of side effects. The first part of the article is focused on the differential diagnosis of phototoxic and photoallergic reactions. A list of the most important drugs that have been implicated as photosensitizers, main principles of diagnosis of drug-induced photosensitivity, as well as its treatment and prevention are also mentioned.
Keywords: drug, photosensitivity, photosensitizer, phototoxicity, photoallergy
