Classification and external resources

Ainhum of the left foot of a Zulu patient in Ngwelezane Hospital, KZN, South Africa.(The little toe on the opposite foot had auto-amputated several years earlier.)
ICD-10 L94.6
ICD-9 136.0
OMIM 103400
DiseasesDB 29442
eMedicine derm/594
MeSH D000387

Ainhum (also known as bankokerend, dactylolysis spontanea, and sukhapakla[1]:607) is a painful constriction of the base of the fifth toe frequently followed by bilateral spontaneous amputation (autoamputation) a few years later. The disease occurs predominantly in black Africans and their descendants. The exact etiology is still unclear.



Ainhum was first reported as a distinct disease and described in detail by J. F. da Silva Lima in 1867.[citation needed] He recognised a disease of the fifth toe suffered by the Nagos tribe of Bahia, Brazil. This disease was called “ainhum” by the Nagos and means “to saw”, characterising the painful loss of the fifth toe. The origin of these term was thought to be African. Due to slave trade, the Nagos were related to a native tribe in Nigeria.


Ainhum predominantly affects black people, living in West Africa, South America and India. In Nigeria it is a common disease with an incidence of 2.2%.[citation needed] Daccarett recorded retrospectively a rate of 1.7% in a mainly African American population in Chicago.[citation needed] Up to now only a few cases had been reported in Europe. Ainhum usually affects people between 20 and 50 years. The average age is about thirty-eight. The youngest recorded patient was seven years old. There is no predominant gender ratio.

Etiology and pathogenesis

The true cause of ainhum remains unclear. It is not due to infection by parasites, fungi, bacteria or virus, and it is not related to injury. Walking barefoot in childhood had been linked to this disease, but ainhum also occurs in patients who have never gone barefoot. Race seems to be one of the most predisposing factors and it may have a genetic component, since it has been reported to occur within families. Dent et al. discussed a genetically caused abnormality of the blood supply to the foot.[citation needed] Peripheral limb angiography in five limbs with ainhum showed that the posterior tibial artery became attenuated at the ankle, and the plantar arch and its branches were absent. The dorsal pedis artery was constituting the only supply to the forefoot and little toe.

Clinical findings

The groove begins on the lower and internal side of the base of the fifth toe, usually according to the plantar-digital fold. The groove becomes gradually deeper and more circular. The rate of spread is variable, and the disease may progress to a full circle in a few months, or still be incomplete after years. In about 75 per cent both feet are affected, though not usually to the same degree.[citation needed] There is no case reported where it begins in any other toe than the fifth, while there is occasionally a groove on the fourth or third toe. The distal part of the toe swells and appears like a small “potato”. The swelling is due to lymphatic edema distal to the constriction. After a time crusts can appear in the groove which can be infected with staphylococcus. While the groove becomes deeper, compression of tendons, vessels and nerves occurs. Bone is absorbed by pressure, without any evidence of infection. After a certain time all structures distal the stricture are reduced to an avascular cord. The toe’s connection to the foot becomes increasingly slender, and if it is not amputated, it spontaneously drops off without any bleeding. Normally it takes about five years for an autoamputation to occur. Cole describes four stages of ainhum:

• Grade I: groove

• Grade II: floor of the groove is ulcerated

• Grade III: bone involvement

• Grade IV: autoamputation has occurred


Pain is present in about 78% of cases. Slight pain is present in the earliest stage of ainhum, caused by pressure on the underlying nerves. Fracture of the phalanx or chronic sepsis is accompanied with severe pain.


Histology shows a change in the prickle cell layer, and this is responsible for the laying down of condensed keratin causing the groove. The junctional tissue is reduced to a slender fibrous thread, almost avascular, and all the tissues beyond the constricting band is repressed by a fibro-fatty mass covered by hyperkeratotic integument.


Soft tissue constriction on the medial aspect of the fifth toe is the most frequently presented radiological sign in the early stages. Distal swelling of the toe is considered to be a feature of the disease. In grade III lesions osteolysis is seen in the region of the proximal interphalangeal joint with a characteristic tapering effect. Dispersal of the head of the proximal phalanx is frequently seen. Finally, after autoamputation, the base of the proximal phalanx remains. Radiological examination allows early diagnosis and staging of ainhum. Early diagnosis is crucial to prevent amputation.

Differential diagnosis

Ainhum is an acquired and progressive condition, and thus differs from congenital annular constrictions. Ainhum has been much confused with other diseases such as leprosy, diabetic gangrene, syringomyelia, scleroderma or Vohwinkel syndrome.


Incisions across the groove turned out to be ineffective. Excision of the groove followed by z-plasty could relieve pain and prevent autoamputation in Grade I and Grade II lesions. Grade III lesions are treated with disarticulating the metatarsophalangeal joint. This also relieves pain, and all patients have a useful and stable foot.


  1. ^ James, William; Berger, Timothy; Elston, Dirk (2005). Andrews' Diseases of the Skin: Clinical Dermatology. (10th ed.). Saunders. ISBN 0-7216-2921-0.

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Look at other dictionaries:

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  • AINHUM — (на языке афр. негров нагосов означает «пила»), эндемический дерматоз некоторых тропических стран, с типичным постепенным стягиванием фиброзным кольцом пальцев, особенно мизинцев стоп, и их дальнейшей самопроизвольной ампутацией.… …   Большая медицинская энциклопедия

  • Ainhum — Ainhum, Krankheit der Eingebornen Afrikas und Südamerikas, bei der sich um die kleine Zehe eine bandartige Verhärtung der Haut bildet, die immer tiefer greift und allmählich die Zehe vollständig abschnürt. Die abgeschnürte Partie schwillt stark… …   Meyers Großes Konversations-Lexikon

  • aïnhum — ● aïnhum nom masculin (mot dialectal d un peuple noir d Afrique du Sud) Affection observée chez les Noirs d Afrique, caractérisée par une bride annulaire étranglant un orteil et évoluant vers l amputation spontanée …   Encyclopédie Universelle

  • ainhum — |a i| s. m. Doença não congênita dos negros do Brasil, caracterizada pelo espessamento progressivo da pele e consequente formação, em torno da raiz de um ou mais dedos do pé, de um anel fibroso, que termina por decepá los …   Dicionário da Língua Portuguesa

  • Ainhum — L ainhum (également connu sous le nom bankokerend, spontanea dactylolysis[1] ou sukhapakla) est une constriction douloureuse de la base du cinquième orteil précédant souvent de longue date (quelques années) une amputation bilatérale spontanée ou… …   Wikipédia en Français

  • ainhum — An acquired slowly progressive painful fibrous constriction that develops in the digitoplantar fold, usually of the little toe, gradually resulting in spontaneous amputation of the toe; most commonly affects black males in the tropics. [fr. Af.… …   Medical dictionary

  • Ainhum — A̲i̲n|hum [in port. Ausspr.: ainjụn̶g̶; afrik. port.] s; s: bei afrik. und südamer. Negern vorkommende Erkrankung unerkannter Ursache, die zur ringförmigen Abschnürung und Abstoßung von Finger oder Zehengliedern (bes. der Kleinzehe) führt …   Das Wörterbuch medizinischer Fachausdrücke

  • ainhum — n. (Medicine) disease common in black adult males in Africa in which a tight and fibrous band develops around the base of a toe or sometimes a finger and eventually causes its spontaneous amputation …   English contemporary dictionary

  • ainhum — ai·nhum …   English syllables

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