Reactive arthritis is a form of arthritis, or joint inflammation, that occurs as a "reaction" to an infection elsewhere in the body. Inflammation is a characteristic reaction of tissues to injury or disease and is marked by swelling, redness, heat, and pain. Besides this joint inflammation, reactive arthritis is associated with two other symptoms: redness and inflammation of the eyes and inflammation of the urinary tract. These symptoms may occur alone, together, or not at all.
Reactive arthritis is also known as Reiter’s syndrome.
The bacterium most often associated with reactive arthritis is Chlamydia trachomatis, commonly known as chlamydia. It is usually acquired through sexual contact. Some evidence also shows that respiratory infections with Chlamydia pneumonia may trigger reactive arthritis.
Infections in the digestive tract that may trigger reactive arthritis include Salmonella, Shigella, Yersinia, and Campylobacter. People may become infected with these bacteria after eating or handling improperly prepared food, such as meats that are not stored at the proper temperature.