Psoriatic arthritis, also called psoriatic arthritis, is a chronic inflammatory arthritis that has the particularity of being associated with psoriasis. Psoriasis is an autoimmune disease in which the immune system becomes disrupted and attacks the skin, causing skin inflammation. With psoriatic arthritis, the immune system also attacks the joints, causing them to become inflamed and possibly causing joint damage if left untreated early. The epidemiological data do not agree from one study to another because the diagnosis is difficult and its criteria do not achieve consensus in the scientific community. Its prevalence would be 0,1 to 1% in the total population. (1) About 15% of people with psoriasis develop psoriatic arthritis. (2)

This arthritis can affect any joint, but it most often affects the large joints of the lower extremities, the joints of the fingers and toes, the back and the pelvis:

• The affected person suffers from nighttime pain and morning stiffness;
• Inflammation of all the joints and phalanges of the fingers and toes (up to the distal interphalangeal joint, at the end of the finger), giving them the appearance of a sausage is characteristic, but not systematic;
• As with rheumatoid arthritis, asymmetric oligoarthritis is often seen progressing to distal and symmetrical arthritis;
• More rarely, the inflammatory affects the spine and the pelvis (the sacroiliac joints), as is the case with ankylosing spondylitis;
• Psoriatic arthritis sometimes leads to episodes of fatigue, anemia and mood swings.

In the majority of cases, the cutaneous involvement precedes the psoriatic arthritis, but the appearance of the cutaneous and articular attacks can be simultaneous. More rarely, joint damage manifests itself first. It is important to stress the fact that psoriatic arthritis can develop in people without psoriasis (it is generally observed that parents have it). The diagnosis is sometimes difficult to establish, the symptoms sometimes directing the doctor, wrongly, towards other types of rheumatism such as rheumatoid arthritis or gout.

We do not know the origin of the disease. 40% of patients have a family member with psoriasis or arthritis, which suggests a hereditary character (2). Psoriatic arthritis can also result from an infection that triggers an immune response, such as a strep infection. The factors of the disease are at the same time genetic, environmental, and immunological.

Psoriatic arthritis affects both men and women and the peak onset of clinical manifestations is between 30 and 50 years. Note that there is juvenile psoriatic arthritis, the prevalence of which is estimated between 3 and 30 children per 100 and is sometimes associated with uveitis. (000)

Early diagnosis followed by appropriate treatment helps prevent joint damage caused by persistent inflammation. In most cases, treatments for psoriatic arthritis are effective in protecting joints and relieving pain. They are based on taking non-steroidal anti-inflammatory drugs and local corticosteroid injections to reduce symptoms. Physical activity and rehabilitation helps maintain good joint capacity. When a joint has suffered damage resulting in loss of mobility, surgery is used. Special attention should be paid to weight, high blood pressure and cholesterol.