Reactive arthritis is classified as a member of the spondyloarthritis family, and shares features with undifferentiated spondyloarthritis, ankylosing spondylitis, psoriatic arthritis, and spondyloarthritis associated with inflammatory bowel disease.
Rheumatoid arthritis (RA) is the most common type of chronic progressive systemic inflammatory disorders that can affect many organs throughout the body, with the joints usually most severely affected. The specific cause of rheumatoid arthritis is unknown. Approximately 1 in every 100 individuals has rheumatoid arthritis. The risk of RA is increased in women who have never been pregnant and in women who have recently given birth. Women to men ratio for RA are about 3:1.
Risk factors for RA include
Sjögren's syndrome (SS) is a chronic inflammatory disorder characterized by diminished lacrimal and salivary gland function. SS occurs in a primary form not associated with other diseases and in a secondary form that complicates other rheumatic conditions. The most common disease associated with secondary SS is rheumatoid arthritis. In primary or secondary SS, decreased exocrine gland function leads to the "sicca complex", a combination of dry eyes (keratoconjunctivitis sicca) and dry mouth (xerostomia).
Systemic lupus erythematosus (SLE) is a chronic inflammatory autoimmune disease that can affect various organs of the body and has a wide variety of clinical pictures. The woman to man ratio in the young adult population is about 8:1 while the ratio in the child and the elderly populations is closer to 2:1. The cause of SLE remains uncertain.