Like many autoimmune diseases, rheumatoid arthritis (RA) can be notoriously difficult to diagnose, especially in the early stages. In fact, nearly half of people diagnosed with RA may actually have another condition, according to a study in the Annals of Rheumatic Diseases.

There’s a whole roster of other conditions, from gout to Lyme disease, that have overlapping symptoms with RA. We're going to break them down so you can get the right diagnosis and the treatment you need, starting with what RA really is first.