Gout is a common, painful form of arthritis. It causes swollen, red, hot and stiff joints.

Gout happens when uric acid builds up in your body. Uric acid comes from the breakdown of substances called purines. Purines are in your body's tissues and in foods, such as liver, dried beans and peas, and anchovies. Normally, uric acid dissolves in the blood. It passes through the kidneys and out of the body in urine. But sometimes uric acid can build up and form needle-like crystals. When they form in your joints, it is very painful. The crystals can also cause kidney stones.

Often, gout first attacks your big toe. It can also attack ankles, heels, knees, wrists, fingers, and elbows. At first, gout attacks usually get better in days. Eventually, attacks last longer and happen more often.

You are more likely to get gout if you:

• Are a man
• Have family member with gout
• Are overweight
• Drink alcohol
• Eat too many foods rich in purines

Gout can be hard to diagnose. Your doctor may take a sample of fluid from an inflamed joint to look for crystals. You can treat gout with medicines.

Pseudogout has similar symptoms and is sometimes confused with gout. However, it is caused by calcium phosphate, not uric acid.

NIH: National Institute of Arthritis and Musculoskeletal and Skin Diseases