What Is Horner Syndrome?
Horner syndrome is a rare condition that causes problems on one side of your face when the nerves there are damaged. It's also called Horner-Bernard syndrome or oculosympathetic palsy.
You can get Horner syndrome at any age. In rare cases -- about 1 in 6,250 births -- a baby will be born with it.
Horner Syndrome Symptoms
These symptoms affect your eyes or face on the same side:
- No sweat on one side of your face
- A droopy upper eyelid (ptosis)
- A lower eyelid that’s slightly raised (inverse ptosis)
- A small pupil, the black circle in the middle of your eye (miosis)
- Pupils that are different sizes (anisocoria)
- A pupil that doesn’t open (dilate) widely or is slow to open in dim light
- A sunken or bloodshot eye
You also can have pain or headaches, which happens more often in middle-aged men.
Horner syndrome can be a sign of a serious health risk such as nerve damage. See your doctor if you notice any of its symptoms.
Symptoms of Horner syndrome in children
Children who get Horner syndrome before age 2 also can have:
- One iris, the colored circle around the pupil, that's a lighter color than the other (heterochromia iridis)
- A lack of flushing on one side of their face on hot days or after playing
Horner Syndrome Causes
In about 35% to 40% of cases, doctors aren’t sure what exactly causes Horner syndrome. Some researchers think it can be tied to your genes.
Other times, it happens because of damage to a string of nerves (called a pathway) that helps control your eyes, heart rate, sweat, and blood pressure. One of three pathways may be involved in Horner syndrome:
First order (central)
This pathway involves the nerves that run from the hypothalamus in your brain to your chest, through your brain stem and spinal cord. Conditions that can affect it include:
- Sudden loss of blood to your brain stem
- Tumors on your hypothalamus
- Spinal cord lesions
- Stroke
- Damage to myelin (a thin sheath around your nerves)
Second order (preganglionic)
These nerves go from your chest to the top of your lungs and along the carotid artery in your neck. They might be affected by:
- Tumors in your upper lung or chest
- Injury or surgery to your neck or chest
Third order (postganglionic)
This path runs from your neck to your middle ear and eye. Things that can affect it include:
- Carotid artery lesions
- Middle ear infections
- Injury to the base of your skull
- Migraine or cluster headaches
Neck or shoulder injuries during birth can cause Horner syndrome in some babies, but it's very rare. Babies born with damage to their aorta can also have it. And neuroblastoma, a type of cancer, can cause it in some kids.
Only 5% of people who have Horner syndrome are born with it.
Horner Syndrome Diagnosis
Your doctor or an eye doctor (ophthalmologist) can do tests to check for Horner syndrome.
They’ll do a physical exam and ask about your medical history to find out if you've had any illness or injury that could have caused nerve damage. Then, they’ll put drops in your eyes to see how your pupils react.
Other tests may show a growth, damage, or injury that could cause Horner syndrome. The doctor might order one or more of these:
- X-rays
- MRI (magnetic resonance imaging). Powerful magnets and radio waves make detailed images.
- CT scan (computerized tomography). Several X-rays from different angles are put together to show a more complete picture.
- Carotid ultrasound. Sound waves make an image of your carotid artery.
Your doctor also may want to test your blood or urine to check for any health problems that could cause nerve damage.
Horner Syndrome Treatment
There aren’t any treatments specifically for Horner syndrome. The best way to ease your symptoms is to treat the health problem that caused them.
If you have a tumor or lesion, your doctor might remove it through surgery. You could also have radiation and chemotherapy.