Rheumatoid arthritis (RA) is a chronic and debilitating illness. It can strike at any age and seems to be more prevalent in women than men. Although the specific etiology (cause) of RA is unknown it is categorized as an auto-immune disease – the body's immune system seems to mistakenly recognize normal tissue as foreign and attack it. Other examples of autoimmune diseases are multiple sclerosis (MS) and Systemic lupus erythematosus (lupus).
The target for the autoimmune reaction in RA is primarily the joints on both sides of the body -wrists, fingers, knees, feet, etc. The extent of the resulting disability can vary widely depending on other factors related to health.