Gout is a common metabolic disorder that causes attacks of arthritis, usually in a single joint (often the base of the big toe).

Gout is due to high levels of uric acid in the blood; the arthritis is due to the deposition of uric acid crystals in joint tissue. The affected joint is red, swollen, and extremely tender. Attacks last for a few days and often recur. They are sometimes accompanied by fever. With recurrent attacks, more joints may be involved, and there may be constant pain due to joint damage from chronic inflammation. In addition, gout may be associated with kidney stones (see calculus, urinary tract) or, rarely, with kidney damage due to the deposition of crystals in the kidney tissue.

The diagnosis is confirmed by tests on blood or fluid from the affected joint to measure uric acid levels.

The pain and inflammation of acute (of sudden onset) attacks can be controlled by nonsteroidal anti-inflammatory drugs (NSAIDs) or by colchicine. If these drugs are ineffective, a corticosteroid drug may be injected into the joint. Many people require no further treatment.

Long-term treatment with drugs that help to lower urate levels, such as allopurinol or sulfinpyrazone, can stop or reduce the frequency of recurrent attacks. These drugs, however, may trigger an attack at the start of treatment, so are initially prescribed with NSAIDs.