Bilateral harlequin syndrome, unilateral Horner syndrome, and Riga-Fede disease as presenting features of hereditary sensory and autonomic neuropathy type IV.

Hereditary sensory and autonomic neuropathy (HSAN) type IV, also known as congenital insensitivity to pain with anhidrosis (OMIM 256800), is part of a family of neurodegenerative disorders that manifest with variable sensory and autonomic neuropathies. In this report, we present a unique dermatological finding in a patient with HSAN type IV: bilateral harlequin syndrome that occurred in association with unilateral Horner syndrome, traumatic alopecia and Riga-Fede disease.