What Are Tophi Deposits?

Tophi deposits are clusters of urate crystals that form deposits in the soft tissues of the body. Deposits of urate crystals can occur almost anywhere but are most frequently seen in cartilage, joints and bones, especially the arm and leg joints. Tophi deposits are common in people who have high levels of uric acid in their bloodstream, a condition that is linked with gout.

Causes

• Tophi deposits are a consequence of high uric acid levels in the blood. The excess uric acid in the bloodstream precipitates out of solution to form urate crystals that cluster together to form tophi deposits. High uric acid levels have a variety of causes but are common in people who have gout.

Signs and Symptoms

• Tophi may be visible on the surface as soft skin nodules, characteristically on the surface of joints of the arms and legs. The outer rim of the ear, called the helix, is another area where tophi deposits commonly appear. These nodules are painless in the early stages and usually don't cause symptoms unless they become chronic. They serve as a marker for high uric acid levels and a high risk for gout. They may be the first sign of gout but are more common after many years of the disease. In chronic, longstanding gout, tophi deposits can become very large.

Complications

• In a person with long-standing gout, tophi deposits can grow large enough to break through the surface of the skin. This causes ulceration and leakage of urate crystals onto the skin surface. In the later stages of gout, tophi deposits may erode into the bone that lies underneath the joint. This can cause pain when moving the affected limb and lead to limitations of movement. Tophi deposits can grow so large and noticeable that they become troubling from a cosmetic standpoint.

Treatment

• Treatment of tophi deposits centers around lowering uric acid levels. Diet and medications are the primary focus of treatment. Dietary management consists of limiting foods and beverages that are high in purines, because purine-rich foods are broken down to form uric acid. There is a long list of foods that are high in purines with the most notable examples being meat and seafood products. Some vegetables are also high in purines, but non-animal sources of purines are less likely to raise uric acid levels. The majority of people with tophi deposits need medications such as allopurinol to lower their uric acid levels. In cases where tophi deposits become large enough to limit movement or are cosmetically unacceptable, they can be surgically excised.