A 45-year-old woman presented with a 10 year history of asymmetrical facial 
flushing and sweating after exertion or in hot weather. During these episodes 
the right side of her face remained dry and white, while the left side normally 
flushed. Sweating was impaired on the left side in the limbs and trunk. She also 
had areflexia in the lower limbs and slow pupillary reactions to light and 
darkness, as seen in Adie's syndrome. The topography of the sweating disorder 
suggested that the lesion involved the sympathetic pathways at the level of 
spinal cord. The relationship with the harlequin syndrome and related disorders 
is discussed.