It is an inflammation of the joints and surrounding tissues, it is chronic, the cause is unknown, it is an autoimmune disease, that is, the body's immune system attacks healthy tissue by mistake.

Treatment: a) to relieve pain (anti-inflammatory and corticosteroid) b) those that serve to modify the disease in the long term: disease-modifying antirheumatic drugs (Fames): methotrexate, sulfasalazine and leflunomide. c) biological therapies: TNF antagonists (etanercept, adalimumab and infliximab), abatacept and rituximab, improve pain and inflammation and prevent joint destruction. If the disease is very advanced, the only solution will be surgery.