The name ainhum is derived from a word in the Nagos language of East Africa meaning “to saw.” It describes the development of constricting bands about digits, almost always the fifth, or smallest, toe, which ultimately undergoes self-amputation. Typically the disease is bilateral (i.e., affecting both small toes).

Ainhum is ordinarily a disease of middle-aged black Africans of both sexes accustomed to going barefoot. The disease is common in Nigeria and East Africa, and has been reported less frequently in other tropical areas, including India, Burma, Panama, the Antilles, and Brazil (Burgdorf and Goltz 1987).

Ainhum was noticed frequently among slaves in Brazil and was first described in detail in 1867 by Brazilian doctor J. F. da Silva Lima who also named the disease. Silva Lima’s description is outstandingly accurate, and has not been bettered. In one case he wrote that the toe had taken the shape of a small oval potato; the covering skin had become coarse and scabrous, and very tender to touch. As the disease progressed, wrote Silva Lima, a strong constriction appeared at the base of the toe, and, as the blood flow to the toe was impeded, the bones ceased to exist. In time, spontaneous amputation of the toe occurred (Cole 1965; Silva Lima 1867).

The cause of ainhum is unknown. According to Walter Burgdorf and Robert Boltz, chronic trauma, infection, hyperkeratosis, decreased vascular supply, and impaired sensation may alone or in combination produce excessive fibroplasia, and lead to ainhum. It is an acquired condition, although a hereditary pre-disposition has not been ruled out (Curban and Moura 1965).