Pentazocine abuse masquerading as familial myopathy

A 58-year-old man and his two young adult children showed fixed abduction of the arms, mild proximal weakness, and muscle induration. The skin over the upper arms, buttocks, and thighs was sclerotic and contained numerous healed punctate ulcers. One patient required skin grafting because of large, active ulcers on both arms. The initial diagnosis was an obscure inherited disorder, but each patient eventually admitted chronic self-injection of pentazocine, which was suspected because of the characteristic clinical findings.