Dactylolysis spontanea

Description, Causes and Risk Factors:

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.

Dactylolysis spontanea 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 cause is still unclear.

The true cause of dactylolysis spontanea 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 dactylolysis spontanea also occurs in patients who have never gone barefoot.

Race and climate apparently are predisposing factors. Dactylolysis spontanea also may have a genetic component, since dactylolysis spontanea has been reported to occur within families. Infection and walking barefoot in childhood are linked to dactylolysis spontanea but probably are not major factors in its development. Abnormal scarring does not appear to be a cause; ainhum and keloid formation rarely occur in the same individual.

Pseudoainhum may be acquired or congenital.

Grades:

Grade I: groove.

• Grade II: floor of the groove is ulcerated.

• Grade III: bone involvement.

• Grade IV: autoamputation has occurred.

Symptoms:

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

The clinical presentation depends on the stage to which the dactylolysis spontaneahas progressed.

The initial sign of a painful fissure under a toe may not be defining, but the progressive constriction at the base of the toe with distal edema is diagnostic of dactylolysis spontanea.

• The toe may become rotated, clawed, and dorsiflexed at the metatarsophalangeal joint.

• Ultimately, before the toe is shed, it may be attached by an increasingly slender thread of fibrous tissue.

Signs:

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 dactylolysis spontanea. Early diagnosis is crucial to prevent amputation.

Diagnosis:

The differential diagnosis of dactylolysis spontanea includes pseudoainhum, which includes a group of conditions such as congenital amniotic bands, bands secondary to specific diseases and traumatic bands. In the hair-thread tourniquet syndrome fibers of hair or thread become tightly wrapped around an appendage of an infant. The treatment is focused on immediately finding and removing the constricting fiber. Surgical exploration is necessary if complete removal cannot be verified. Most cases involving the toes are caused by hair, whereas most cases involving the fingers are caused by thread from mittens. A few cases of labial or penile strangulation were noted, providing yet another reason for physicians to routinely check the diapers of their pediatric patients.

The radiographic manifestations of dactylolysis spontanea are diagnostic. Initially, a radiolucent band can be observed constricting the base of the involved toe, with distal swelling. Osteolysis develops in the distal and middle phalanges, with a characteristic tapering effect. Ultimately, the bone narrows until it fractures and autoamputates. The radiographic appearances in pseudoainhum are similar or identical to true dactylolysis spontanea.

Histologically, dactylolysis spontanea shows fissuring and epidermal hyperkeratosis and parakeratosis, which is followed by a fibrotic reaction under the deepening fissure. The fibrosis is predominately composed of collagen. As scar tissue contracts, it constricts and narrows neurovascular bundles. Histologic appearances in pseudoainhum are similar or identical to those observed in true dactylolysis spontanea.

Treatment:

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 (MTPJ). This also relieves pain, and all patients have a useful and stable foot.

NOTE: The above information is for processing purpose. The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition.

DISCLAIMER: This information should not substitute for seeking responsible, professional medical care.