Buerger's disease (thromboangiitis obliterans) is a problem with the smaller blood vessels of the arms and legs. Inflammation, which is part of the body's immune response, happens in these blood vessels. That causes clumps of cells to form clots. The clots can reduce or block blood flow in the blood vessels. That makes it hard for blood and oxygen to reach the ends of your arms and legs.
The lack of blood and oxygen can damage the tissues in your fingers and toes, which can be very painful. In serious cases, the tissue might die.