Ainhum (from Portuguese, ), also known as dactylolysis spontanea, is a painful constriction of the base of the fifth toe frequently followed by bilateral spontaneous autoamputation a few years later.
Signs and symptoms
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 percent of cases both feet are affected, though not usually to the same degree. It has even been seen in psoriasis or it is acquired by the wrapping toes, penis or nipple with hairs, threads or fibers. Oral retinoids, such as tretinoin, and antifibrotic agents like tranilast have been tested for pseudo-ainhum.
Prevention
Wearing shoes to protect barefoot trauma has shown decrease in incidence in ainhum. Congenital pseudoainhum cannot be prevented and can lead to serious birth defects. Ainhum occurs worldwide, but is most common in people of sub-Saharan African origin. It is more common in men than in women (2:1) between 20 and 50 years of age.
History
The first description of ainhum in the West appears to have been provided by English surgeon Robert Clarke, who made a passing reference to "dry gangrene of the little toe" as a common occurrence in the Gold Coast in an 1860 report to the Epidemiological Society of London, but did not recognize it as a distinct entity and believed it to be a consequence of "suppressed yaws". Ainhum was first recognized as a distinct disease and described as such in detail by Brazilian physician José Francisco da Silva Lima (1826–1910), in 1867. The name "ainhum" (from the Yoruba ayùn, meaning "to saw" or "to file") was used to refer to the disease by Yoruba speakers in Bahia, Brazil, where Silva Lima practiced.