Ainhum

Ainhum is a progressive, spontaneously constricting dactylolysis, primarily affecting the fifth toe, leading to its auto-amputation. It's most commonly observed in Black populations indigenous to tropical Africa, although it can occur in other populations, albeit rarely.

Ainhum presents initially as a groove or fissure on the plantar aspect of the digit, usually at the level of the interphalangeal joint. Over time, this groove deepens and slowly constricts the toe, disrupting circulation. This constriction eventually leads to distal swelling, pain, ulceration, and ultimately, necrosis and auto-amputation of the affected digit.

While the exact etiology of ainhum remains unclear, several factors are thought to contribute. These include walking barefoot on hard, uneven surfaces, trauma, infection, and possibly genetic predisposition. Some classify ainhum as either true (idiopathic) or pseudo-ainhum, where the constriction is secondary to other underlying conditions such as psoriasis, keratoderma, syringomyelia, or vascular disease.

Diagnosis is typically clinical, based on the characteristic presentation of the constricting band on the toe. Radiographic examination may reveal bone resorption at the site of constriction.

Treatment options depend on the stage of the condition. Early stages may be managed conservatively with hygiene, topical medications, and padding to prevent further trauma. Surgical intervention, such as excision of the constricting band or amputation of the affected digit, may be necessary in more advanced cases.