Gout, joint pain Gout is a painful type of inflammatory arthritis that happens when uric acid builds up in the body and forms crystals in or around a joint. These crystals can cause sudden episodes of intense pain, swelling, redness, warmth, and tenderness. Gout often affects one joint at a time, commonly the big toe, but it can also affect the ankle, foot, knee, wrist, elbow, or fingers. The CDC notes that gout causes periods of severe pain and swelling called flares, and th