/content/imprint/oecd. 1  Browse by Theme Agriculture and Food. Development. 2  Browse by Country A-C. D-I. 3  Browse by Theme & Country Select one or more items in one or both lists to browse for the relevant content. Theme Select / Clear all.  Catalogue BOOKS. PAPERS.
A variety of factors -- ranging from emotional stress and trauma to streptococcal infection -- can cause an episode of psoriasis. Recent research indicates that some abnormality in the immune system is the key cause of psoriasis.
Not everyone who has psoriasis will get psoriatic arthritis, even though the conditions are often related. Psoriasis causes patches of scaly, red, or white skin called plaques. Psoriatic arthritis sets off joint swelling and pain that can lead to permanent damage. Your immune system is responsible for both. Inflammation is part of both psoriasis and psoriatic arthritis.