Horner syndrome is a rare condition characterized by miosis (constriction of the pupil), ptosis (drooping of the upper eyelid), and anhidrosis (absence of sweating of the face). It is mainly caused by damage to the sympathetic nerves of the face.
Horner syndrome has several names such as Bernard-Horner syndrome (French-speaking countries), Horner syndrome (English speaking countries), oculosympathetic palsy and Von Passow syndrome.
The causes of Horner syndrome
The abnormalities in the eye area related to Horner syndrome do not generally affect vision or health. However, the nerve damage that causes Horner syndrome may result from health problems that could be life-threatening.
The following can cause Horner’s syndrome:
- Cysts or tumors
- Damage to your aorta (the main blood vessel to your heart) or the myelin (a thin sheath around your nerves)
- Infection at the base of your skull
- Injuries to your carotid artery or jugular vein, which carry blood through your neck
- Migraines and cluster headaches
- Multiple sclerosis
Neck or shoulder injuries during delivery can cause Horner syndrome in some babies, but it’s very rare. Babies born with damage to their aorta can also develop the condition.
Only 5% of people who have Horner syndrome are born with it. Sometimes, there’s no known reason for it. This is known as idiopathic Horner syndrome.
Your doctor may be able to diagnose Horner syndrome based on your history and his or her assessment of your symptoms. By comparing the reactions in the healthy eye with that of the suspect eye, your doctor can determine whether nerve damage is the cause of problems in the suspect eye.
The use of eye drops is a common cause of a harmless change in pupil size. Other liquid medicines that are dropped in the eyes, including medicine from asthma inhalers, can change pupil size. Therefore consult a professional before you diagnose yourself.
Symptoms of Horner syndrome
When observed in room light, the anisocoria (inequality of pupil size) in Horner syndrome may be as little as 1 mm or even less. In darkness, the anisocoria is increased and the effected pupil dilates more slowly than normal. Paying close attention to small details is important. Keep a lookout for certain symptoms.
These are the symptoms of Horner syndrome:
- A pupil that is smaller than the pupil of the other eye and does not dilate (enlarge) in dim light
- Ptosis of the eyelid on the affected side of the face
- Inverse ptosis (i.e., a raised lower eyelid)
- Sunken appearance of affected eye
- A large area of skin that does not perspire on the affected side of the face (anhydrosis)
In small children, Horner syndrome can sometimes present additional symptoms:
- The skin on the affected side of the face may not flush (redden) under conditions that would normally cause flushing (by physical exertion, heat, or emotional stress). In some cases the reverse may occur—the affected side of the face will have a perpetually flushed appearance.
- The iris of the affected eye may have a lighter color than the unaffected eye.
Treatment of Horner syndrome
Treatment of Horner syndrome depends on the cause. Signs and symptoms usually go away after the cause is treated. You may need either of the following:
- An ophthalmologist (eye specialist) may be able to find and treat vision problems that develop.
- Occupational therapy may be helpful if you have trouble seeing because of eyelid drooping. An occupational therapist can help you strengthen affected eye muscles. The therapist can also help you find ways to do your work or daily activities more easily if you are having vision problems.
- Surgery or medication may be used if you have severe eyelid drooping.
- Clot-dissolving agents, for specific types of stroke.
- Antibiotics or antiviral drugs, for infectious causes.
- Anti-inflammatory drugs (e.g., for horner syndrome linked to multiple sclerosis).
Horner syndrome often resolves, but it may become permanent after repeated attacks.
Due to Horner syndrome, a person may not be able to sweat (perspire), which can lead to hazardous effects. When you don’t sweat, your body can’t cool itself, which can lead to overheating and sometimes to heatstroke — a potentially fatal condition. Therefore, get treatment before the syndrome becomes permanent.
Horner syndrome may affect your pets
Horner syndrome affects cats and dogs alike. Humans are not the only ones who should be vigilant about the onset of this condition. Your pets may be at risk too.
Horner syndrome symptoms are unmistakable, therefore, the cause behind the syndrome becomes the primary point of importance. A veterinarian will likely ask whether you suspect your pet has fallen or been in a fight.
If you are experiencing any of the symptoms of Horner syndrome, it is important that you make an appointment with a medical professional and get yourself checked immediately.