The word ainhum is derived from a term in the Nagos language of East Africa meaning “to saw.” It describes the development of constrict-ing bands about digits, almost always the fifth, or smallest, toe, which ultimately undergoes self-amputation. Typically the disease is bilat-eral (i.e., affecting both small toes).
Ainhum is ordinarily a disease of middle-aged black Africans of both sexes accustomed to go-ing 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.
Ainhum was noticed frequently among slaves in Brazil and was first described in detail in 1867 by J. 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 was coarse and scabrous and tender to touch. As the dis-ease progressed, a strong constriction appeared at the base of the toe, and, as blood flow to the toe was impeded, the bones ceased to exist. In time, spontaneous amputation occurred.
The cause of ainhum is unknown. 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 predisposition has not been ruled out. Surgery is the mainstay of therapy: In most cases, prompt amputation may save the patient pain and infection.