Horner syndrome usually affects only one side of the face. Common signs and symptoms include:  A persistently small pupil (miosis) A notable difference in pupil size between the two eyes (anisocoria) Little or delayed opening (dilation) of the affected pupil in dim light Drooping of the upper eyelid (ptosis) Slight elevation of the lower lid, sometimes called upside-down ptosis Sunken appearance of the affected eye Little or no sweating (anhidrosis) on the affected side of the face  Signs and symptoms, particularly ptosis and anhidrosis, may be subtle and difficult to detect. Children Additional signs and symptoms in children with Horner syndrome may include:  Lighter iris color in the affected eye of a child under the age of 1 Change in color on the affected side of the face that would typically appear from heat, physical exertion or emotional reactions 
horner syndrome affects only side face  common signs symptoms include:  persistently small pupil (miosis) notable difference pupil size eyes (anisocoria) little delayed opening (dilation) affected pupil dim light drooping upper eyelid (ptosis) slight elevation lower lid  called upside-down ptosis sunken appearance affected eye little sweating (anhidrosis) affected side face  signs symptoms  ptosis anhidrosis  may subtle difficult detect  children additional signs symptoms children horner syndrome may include:  lighter iris color affected eye child age 1 change color affected side face typically heat  physical exertion emotional reactions 
horner syndrome