Psoriatic arthritis psoriatic arthritis, and affect them symmetrically. Involvement of the spinal joints is more suggestive of psoriatic arthritis than rheumatoid arthritis. Osteoarthritis shares certain clinical features with psoriatic arthritis such as its tendency to affect multiple distal joints in an asymmetric pattern. Unlike psoriatic arthritis, osteoarthritis does not typically involve inflammation of the sacroiliac joint. Psoriatic arthritis sometimes affects only one joint and is sometimes confused for gout or pseudogout when this happens. There are five main types of psoriatic arthritis: The underlying process in psoriatic arthritis is inflammation; therefore, treatments are directed at reducing and controlling inflammation. Milder cases of
Juvenile idiopathic arthritis migration inhibitory factor has been associated with this condition. It is sometimes called "adolescent-onset Still's disease", to distinguish it from adult-onset Still's disease. However, some evidence shows the two conditions are closely related. Rheumatoid factor and ANA are generally negative in systemic JIA. Some doctors include two other, less common forms: enthesitis-related arthritis and psoriatic JIA. Enthesitis is an inflammation of the insertion points of the tendons. This form occurs most often in boys older than 8, large joints of lower extremities are commonly affected; characteristically, it causes back pain, and is linked to ankylosing spondylitis and inflammatory bowel disease.