Horner’s syndrome is a rare condition that affects the face. Symptoms typically affect only one side of the face, and may include a drooping eyelid, a constricted pupil, and the absence of facial sweating.
Horner’s syndrome occurs due to a interruption anywhere along the sympathetic nerve pathway from the brain to the face. Medical professionals may refer to Horner’s syndrome as oculosympathetic palsy or Bernard-Horner syndrome.
This article provides an overview of Horner’s syndrome, including its symptoms, types, causes, and risk factors. We also provide information on diagnosing, treating, and preventing Horner’s syndrome, and when to see a doctor.
Horner’s syndrome is a rare condition, affecting approximately
Interference with the sympathetic nerves that connect the brain and the face causes Horner’s syndrome.
The sympathetic nerves are part of the autonomic nervous system. Driven by epinephrine, these nerves involuntarily control many body functions, especially during stressful episodes when the body enters the “fight-or-flight” mode.
Involuntary functions include:
- pupil dilation and constriction
- contraction of the Müller muscle of the upper eyelid
Although the symptoms of Horner’s syndrome do not significantly affect a person’s health, they can indicate an underlying health issue that requires investigation.
According to the National Organization for Rare Disorders (NORD), Horner syndrome usually affects only one side of the face. Possible signs and symptoms include:
The sympathetic nerves that connect the brain with the face and eyes travel along three pathways.
According to the American Academy of Ophthalmology, an obstruction along any one of these pathways may lead to one of three types of Horner’s syndrome. These are outlined below.
First-order Horner’s syndrome
First-order Horner’s Syndrome involves any interruption of the nerve pathway that runs from the hypothalamus, through the brain stem to the cervical spinal cord. Disruptions along this pathway
- interrupted blood flow to the brain stem
- spinal injury
- spinal cord lesions
- a thyroid tumor
- multiple sclerosis
Second-order Horner’s syndrome
Second-order Horner’s syndrome involves obstruction to the nerve pathway that runs from the chest, through the lungs, and into the carotid artery of the neck. A blockage along this pathway
- a tumor at the top of the lung
- injury or lesions in the chest cavity
- a neck injury
- certain types of dental abscess
- surgery to the head or neck
Third-order Horner’s syndrome
Third-order Horner’s syndrome involves obstruction to the nerve pathway that travels from the neck to the middle ear and eye. A blockage along this pathway
In clinical practice, no treatable lesion is identified in the vast majority of Horner’s syndrome cases. When a cause is identified, it is usually due to a lesion or growth somewhere along the sympathetic nerve pathway between the hypothalamus of the brain and the eye.
Some conditions that can cause Horner’s syndrome include:
- head or neck injury or lesion
- a tumor at the top of the lung
- lung cancer
- ear infections
- cluster headaches
- a lack of blood supply to the brain
- surgical complications
Some cases of Horner’s syndrome are idiopathic, meaning they occur without a known cause.
Some researchers believe that Horner’s syndrome can also have a genetic cause in certain cases.
- injury or trauma to the sympathetic nerves
- a tumor in the lungs, thyroid gland, or hypothalamus
According to NORD, some clinical researchers believe that certain cases of Horner’s syndrome are inherited, meaning they can be passed from parents to their children.
Pancoast tumors are an
- numbness, tingling, or a loss of sensation in the hands
- reduced sweating on one side of the face
- ptosis and miosis
When diagnosing Horner’s syndrome, a doctor will begin by asking about a person’s symptoms and performing a physical examination.
If the doctor suspects Horner’s syndrome, they may refer the patient to an ophthalmologist, a doctor who specializes in diagnosing and treating eye conditions.
The ophthalmologist will sequentially administer two diagnostic eyedrops in both eyes and measure the pupillary response. Comparing the reactions in both eyes helps the ophthalmologist to localize any nerve damage. Most patients have third-order Horner’s syndrome and require no additional clinical workup.
If diagnostic testing indicates first- or second-order sympathetic nerve involvement, one or more of the
The treatment for Horner’s syndrome
Depending on the cause, treatment options may include:
The outlook for people living with Horner’s syndrome depends mainly on the cause of the condition.
For people with idiopathic Horner’s syndrome, the condition remains relatively benign, with many experiencing a partial or complete resolution of their symptoms.
People who develop Horner’s syndrome secondary to an underlying cause may experience complications relating to the underlying cause. A person can talk with their doctor about their individual treatment options and outlook.
Some types of Horner’s syndrome are not preventable, such as inherited and idiopathic types.
However, underlying conditions, such as trauma, infection, or tumors, cause most cases of Horner’s syndrome. While it is not always possible to prevent such causes, the following may help reduce a person’s risk:
- wearing protective equipment to protect against injury when playing sports
- maintaining good personal hygiene to reduce the risk of infections
- stopping smoking, if a person smokes, to reduce the risk of lung cancers
- following a health-promoting diet and maintaining a moderate weight to help
reduce the riskof certain cancers
It is important to note that Horner’s syndrome is a group of symptoms that may indicate an underlying health issue. As such, anyone who experiences symptoms of Horner’s syndrome should see their doctor for a formal diagnosis.
A person should also see their doctor if symptoms of Horner’s syndrome develop suddenly or immediately following a head injury. More serious conditions like stroke can cause symptoms such as eyelid drooping or a constricted pupil.
Below are some answers to commonly asked questions about Horner’s syndrome.
Is Horner’s syndrome life-threatening?
Horner’s syndrome is a group of symptoms that an underlying health issue may cause. Horner’s syndrome itself is
What are the four classic signs of Horner’s syndrome?
The four characteristic signs of Horner’s syndrome are:
- a constricted pupil
- a drooping eyelid
- a sunken eyeball
- reduced or absent sweating on one side of the face
What cranial nerve is damaged in Horner’s syndrome?
Any damage to the three distinct segments of the sympathetic nervous system could lead to Horner’s syndrome. The sympathetic nerve connects the brain to the face, enabling functions such as pupil dilation and constriction, and sweating.
Horner’s syndrome is a rare condition that affects the face. The four characteristic signs and symptoms include a constricted pupil, a drooping eyelid, a sunken eye, and reduced or absent sweating on the affected side of the face.
An interruption of the sympathetic nerve pathway connecting the brain and the face causes Horner’s syndrome. Disruption of the sympathetic nerve pathway may occur as a result of injury, infection, or disease. Some cases may have a genetic cause, whereas most are benign and idiopathic.
Anyone who experiences signs and symptoms of Horner’s syndrome should see their doctor to determine the cause. Horner’s syndrome can sometimes indicate a serious underlying health issue that requires immediate attention.