Reactive arthritis will not spread from one person to another on its own, but the bacteria that trigger it are contagious. Sometimes reactive arthritis can be genetic in nature. The cause for reactive arthritis can be venereal infection and Chlamydia Trachomatis is the most common bacterium responsible for it. If the infectious dysentery is contracted in the bowel then bacterium organisms in it such as shigella, salmonella cause infection. After 3 to 4 weeks of getting attacked by the infection, reactive arthritis gets triggered. However, all people who get venereal infection do not develop reactive arthritis. Thus, studies are still going on to find the exact cause of the disease.

When a body part gets infected such as intestine, genitals and urinary tract, in response to this infection, the body develops autoimmune response which is known as reactive arthritis. The bacteria can pass from one person to another either through food or through sexual contacts, but every person exposed to these bacteria does not develop reactive arthritis because of the resistance power of their body. It affects people in the age group 20 to 40 years. Effects of reactive arthritis are inflammation of joints, sexual organs within the body.