Untreated hammer toe may progress to more severe deformity, and from flexible to stiff deformity. As the deformity worsens, the risk of developing other complications, like ulcers, calluses, arthritis in other joints and an abnormal gait increases. The deformity may also lead to disease in the nail, including ingrown and broken nails. All of these factors can lead toworsening pain and difficulty walking.
Occasionally, ulcers that form around the deformed toe can become infected. The infection can spread into the soft tissues deep to the skin, and even spread into the bone causing osteomyelitis. This is a rare serious complication that is more common in diabetics.