<unk>  is a general term for a form of joint inflammation<unk>  that develops as a "reaction" to an infection in another area of the body (i.e., outside of the joints). Joint inflammation is characterized by redness, swelling, pain and warmth in and around the affected joint. In<unk> , the large joints of the lower limbs and the sacroiliac joints are most often affected. Two other common symptoms of<unk>  are inflammation of the urinary tract and inflammation of the membrane (conjunctiva) that lines the eyelids (conjunctivitis). These three characteristic symptoms may occur separately, all at once or not at all. Additional symptoms such as fever, weight loss, lower back pain and heel pain may also occur.<unk>  usually develops following a bout with certain bacterial infections including Chlamydia, Salmonella, Shigella, Yersinia, and Campylobacter.<unk>  belongs to a group of related disorders known as the spondyloarthritidies. These disorders are linked by the association of similar symptoms and a specific genetic marker called HLA-B27. Symptoms common to these disorders include<unk> , especially of the lower limbs, lower back pain and enthesitis, a condition characterized by inflammation at the spot where tendons attach to bone. This group of disorders includes<unk> , ankylosing spondylitis, psoriatic<unk> , undifferentiated spondyloarthritis and spondyloarthritis associated with inflammatory bowel disease.<unk>  is a poorly defined disorder that has been described in the medical literature under many different names. No precise diagnostic or classification criteria have been developed that are universally agreed upon in the medical community.
Reactive arthritis
Rheumatoid arthritis
Psoriatic arthritis
Crystal arthritis
Juvenile idiopathic arthritis
Oligoarthritis
Enteropathic arthropathy
Septic arthritis