Pseudoporphyria is a phototoxic dermatitis clinically and histologically dosely resembling porphyria cutanea tarda (PCT), but without enhanced urinary and faecal excretion of higher-carboxylic porphyrins. Photosensitivity is basically caused by natural or arteficial UVA- or visible radiation. The disease is induced either by metabolic factor (higher plasma concentration of porphyrins in patients with chronic renal failure on hemodialysis) or by different drugs and their components (frequently by NSAIDs), by cosmetic products, suntan lotions, long-acting ingredients of nutrition products, and by hormones. Also immunity pattern of the patient may play a role in its origin. As far as therapy of pseudoporphyria is concerned, only elimination of noxious influence of known photosensibilizing drugs and of the exposure to the radiation of the above spectral regions leads to healing of skin changes.

        Key words: pseudoporphyria - porphyria - PCT - phototoxicity - photosensitizing drugs - photoder-matoses - solária - PUVA