Allopurinol-associated hand and foot deformities in chronic tophaceous gout.

Telescoped digits of the hands and feet developed in a 69-year-old male with severe chronic tophaceous gout during allopurinol treatment. Extensive osseous tophi, resorbed rapidly during therapy with this xanthine oxidase inhibitor and not replaced by new bone matrix, were responsible for the deformity. Several hypotheses are advanced to explain the failure of bone erosions to heal.