&Other Spondyloarthropathies=The terms spondyloarthritis, spondyloarthritides, spondyloarthropathy, and spondyloarthropathies are used to refer to a family of diseases that share certain clinical features. The most distinguishing features are inflammation of axial joints (especially the sacroiliac joints), asymmetric oligoarthritis (especially of the lower extremities), and enthesitis (inflammation at sites of ligamentous or tendon attachment to bone). Additional features are genital and skin lesions, eye and bowel inflammation, an association with preceding or ongoing infectious disorders, and a strong association with the human leukocyte antigen (HLA) B27 . The SpA family consists of the following disorders: Undifferentiated spondyloarthritis (USpA); Ankylosing spondylitis; Reactive arthritis (formerly called Reiter syndrome); SpA associated with psoriasis or psoriatic arthritis; SpA associated with Crohn's disease and ulcerative colitis; Juvenile onset spondyloarthritis. Inflammatory back pain is the most common symptom at disease onset, being present in about 70 percent of patients. The peripheral arthritis in SpA usually has an acute onset and predominantly involves the lower extremities, especially the knees and ankles. However, any joint can be involved. Arthritis is typically asymmetrical and often affects only one to three joints. Arthritis of the knees and ankles can be accompanied by considerable swelling. The most common observable clinical manifestation of enthesitis is swelling at the heels, at the insertion of the Achilles tendon, or the insertion of the plantar fascia ligament into the calcaneus. They are usually associated with severe pain and tenderness. A characteristic feature of SpA is dactylitis, also known sausage toe or sausage finger. Unlike synovitis, in which swelling is confined to the joints, with dactylitis the entire digit is swollen. Joints do not show the discrete palpable fusiform swelling of synovitis, and there may be surprisingly little pain or tenderness. The diffuse swelling arises from flexor tendon, sheath, and marked adjacent soft tissue involvement. Dactylitis is not specific for SpA and may also be seen when the bones of the digits are involved with tuberculosis, syphilis, sarcoidosis and sickle cell disease. Sausage-like swelling of one or more digits may also occur with tophaceous gout.