You are sent a picture of a 44-year-old woman taken just after she had run a distance of one mile. What is your diagnosis and what test(s) would you order to investigate this disorder?
DIAGNOSIS: Harlequin syndrome (HS), a rare dysautonomia which is characterized by periodic hemifacial flushing and sweating, typically brought on by exercise, heat, or emotional stress. The syndrome can occur alone (two-thirds) or in association with other dysautonomic disorders, including Horner, Holmes Adie, and Ross syndromes (one-third). The dysfunction involves the sympathetic nervous system on the pale side of the face, which is normally responsible for dilating the cutaneous vasculature and initiating sweating in response to heat stress and emotion. This patient's HS was due to a tumor of a cervical sympathetic ganglion on the side of pallor (arrow), and resolved after the tumor was removed.
For users of the touch screen - please do not migrate off the medical mystery site