Hanging on by a thread: a rare case of secondary pseudoainhum.

Pseudoainhum is a rare and poorly characterised phenomenon involving autoamputation of a digit associated with an identifiable or related disease process. We describe the case of a 19-year-old man with long-standing neurodisability, sensorineural hearing loss and severe keratoderma, presenting with painless rapidly-progressing autoamputation of his left little toe. Genetic analysis thus far has been inconclusive. The toe appeared to be hanging on by a thread, with no clinical signs of infection. Radiographs showed lysis with complete resorption of the proximal phalynx. Routine blood tests found an isolated neutropenia with normal C reactive protein and biochemistry. We report an unusual case of a young adult with a history of chronic neurological and dermatological problems presenting with secondary pseudoainhum and provide a valuable addition to the limited literature describing this rare condition. 2016 BMJ Publishing Group Ltd.