Psoriatic arthritis is an inflammatory condition where polyarthritis is joined with psoriasis (a skin disease). It can spread from peripheral joints to the spine, and is then called psoriatic spondylitis.
Psoriasis is a non-contagious skin disease of unknown cause. Causes are often connected to antigens of B13, B17, and B37 tissue correspondence. On the patient’s skin are visible red spots covered with whitish peel that is easily removed and seems like it’s made from wax. Patients that suffer from psoriatic arthritis skin changes are usually most prominent near the joints affected. Usually psoriasis manifests first, and arthritis later, but it can also be other way around. Most patients develop the illness in a manner of peripheral polyarthritis, which means it usually affects several joints. On the hands all small finger joints are affected, and nails also show signs of psoriatic changes – they are yellow, thick and brittle. Often is a single finger affected with inflammation of both the joint and tendon capsule, so it thickens visibly.
Destruction of bone near the joint can be vast, so developing a „mutilated fist“ is quite characteristic. Joint changes do not appear symmetrically like in rheumatoid arthritis, so arthritis can appear unilaterally, e.g. only in the left knee.
Inflammatory effect of this illness is proven with lab test (enhanced red blood cell sedimentation), but since there is usually no rheumatoid factor in the blood, this illness is nowadays considered one of „seronegative spondyloarthropathies“.
Prognosis is often inconclusive, but not very good due to significant deformations. Eye complications are also possible, like iritis, conjunctivitis, episcleritis and dry keratoconjunctivitis.
Treatment must have two parts – we must treat both the skin and the joint. Joint disease is treated similarly like rheumatoid arthritis, and skin disease needs local and systematic application of retinoids, corticosteroids, and UV therapy. Hydrotherapy in the pool with regular water is not allowed because of psoriasis (skin would be irritated from disinfectants), but sea water, sulphur water, and naphtalane have a very positive effect on psoriasis.