Recurrent digital infections and osteomyelitis in monozygotic twins with congenital analgesia and compulsive onychophagia.

Congenital insensitivity to pain is a rare sensory neuropathy that manifests with multiple and recurrent injuries secondary to a lack of negative pain stimuli. When present with compulsive onychophagia, prompt recognition and behavioral management to prevent chronic digital infection or amputation is imperative. We present the case of two 7 year-old monozygotic twins that presented with congenital insensitivity to pain and compulsive onychophagia without directed parental counseling or behavioral modification strategies. The presenting child was noted to have an acute digital felon and osteomyelitis of several distal phalanges, and the sister had a similar history with distal phalangeal amputations. The occurrence of these overlapping disorders in monozygotic twins has not been previously reported, however, patient and parental education with behavioral modifications of injurious and compulsive behavior is the cornerstone of management. In addition, we have provided a review of the diagnosis for clinical differentiation.