Table of ContentsView AllTable of ContentsSymptomsCausesUnderlying ConditionsDiagnosisTreatment
Table of ContentsView All
View All
Table of Contents
Symptoms
Causes
Underlying Conditions
Diagnosis
Treatment
Horner syndrome doesn’t occur on its own but develops as a result of another medical condition, such as a stroke, brain tumor, or spinal cord injury. The treatment is focused on resolving the underlying cause.
The article describes the symptoms and causes of Horner syndrome, including how this uncommon neurological syndrome is diagnosed and treated.
What Are the Symptoms of Horner Syndrome?
Classically, Horner syndrome describes a group of three symptoms that occur concomitantly (at the same time):
The symptoms are unilateral (affecting one side of the face only).
Other possible symptoms include unilateral facial flushing, blurred vision, or eye pain. In some cases, facial anhidrosis may affect the entire left or right side of the face or just a portion of it (such as the forehead).
Additional symptoms may appear depending on the underlying cause. (An example is the loss of bladder control following a stroke,) These are not considered facets of Horner syndrome. Rather, Horner syndrome is regarded as secondary to the underlying cause.
Horner syndrome occurring in newborns may also causeiris heterochromia. This occurs when the iris (the colored part of the eye) appears lighter on the affected side.
What Is Horner Syndrome Caused By?
With Horner syndrome, a specific part of the sympathetic nervous system, called theoculosympatheticpathway, is damaged.
Under normal circumstances, activation of the oculosympathetic pathway will cause your eyelids to open (to better see the threat), your pupils to widen (to see better in the dark), and your face to sweat (to cool it down as your body is flooded with inflammatory chemicals).
When any part of the oculosympathetic pathway is disrupted—from thehypothalamusandbrainstemof the brain to thecervicalandthoracic spineof the neck and chest—Horner syndrome can occur.
The intensity of symptoms depends on how severely the nerve pathway is damaged.
How the Autonomic Nervous System Works
The oculosympathetic pathway is divided into three parts, each of which can cause Horner syndrome. Different conditions can affect these different parts.
First-order Horner syndromeinvolves damage to the nerve running from the hypothalamus and brainstem to the spinal cord. Conditions affecting this section include:
Second-order Horner syndromeinvolves damage to the nerve running from your chest to the top of your lungs and along thecarotid arteryof your neck. Conditions affecting this section include:
Third-order Horner syndromeinvolves damage to the nerve running from your neck to your middle ear and eye. Conditions affecting this section include:
In some cases, the cause of Horner syndrome is idiopathic, meaning of unknown origin.
Horner Syndrome in Children
There is a rare form of Horner syndrome called “congenital Horner syndrome” that can be passed from parents to a child. It is anautosomal dominant disorder, meaning that the condition can develop if a single copy of the gene mutation is passed from one parent.
Congenital Horner syndrome accounts for only 5% of cases among children.
How Horner Syndrome Is Diagnosed
While the triad of “classic” symptoms may provide ample evidence of Horner syndrome, it is important to remember that Horner syndrome is not the cause but rather the effect of some other condition.
To this end, your healthcare provider will want to perform tests to first confirm Horner syndrome and then narrow the list of possible causes.
The diagnosis will start with a detailed medical history and physical exam. As part of the exam, the healthcare provider may use eyedrops containingapraclonidineto see if they dilate (widen) the pupil as they are meant to. Failure to do so is an indication of nerve damage.
Next, the healthcare provider will order tests to pinpoint where along the oculosympathetic pathway the injury has occurred. These may involve imaging tests such as:
Additional tests may be ordered, depending on the suspected cause.
Horner Syndrome Treatment
The treatment for Horner syndrome varies based on the underlying cause. The treatment does not “cure” Horner syndrome but rather resolves or minimizes the underlying cause.
Potential treatments may include:
Different medical specialists may be involved in the treatment, such as pulmonologists, neuro-ophthalmologists, and oncologists.
In many cases, the symptoms of Horner syndrome will go away once the underlying condition is resolved. In other cases, the symptoms may resolve on their own without treatment.
Summary
Horner syndrome is a neurological disorder that affects the eye and surrounding tissues on one side of the face. Symptoms include the drooping of the upper eyelid, a constricted pupil, and absent sweating on one side of the face.
3 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Barrea C, Vigouroux T, Karam J, et al.Horner syndrome in children: a clinical condition with serious underlying disease.Neuropediatrics. 2016;47(4):268-72. doi:10.1055/s-0036-1584085NIH Genetics Home Reference.Horner syndrome.Horner’s syndrome: genetic and rare diseases information center (GARD) – an NCATS Program. National Center for Advancing Translational Sciences (NIH).Additional ReadingNIH. Genetics Home Reference.Horner Syndrome.
3 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Barrea C, Vigouroux T, Karam J, et al.Horner syndrome in children: a clinical condition with serious underlying disease.Neuropediatrics. 2016;47(4):268-72. doi:10.1055/s-0036-1584085NIH Genetics Home Reference.Horner syndrome.Horner’s syndrome: genetic and rare diseases information center (GARD) – an NCATS Program. National Center for Advancing Translational Sciences (NIH).Additional ReadingNIH. Genetics Home Reference.Horner Syndrome.
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Barrea C, Vigouroux T, Karam J, et al.Horner syndrome in children: a clinical condition with serious underlying disease.Neuropediatrics. 2016;47(4):268-72. doi:10.1055/s-0036-1584085NIH Genetics Home Reference.Horner syndrome.Horner’s syndrome: genetic and rare diseases information center (GARD) – an NCATS Program. National Center for Advancing Translational Sciences (NIH).
Barrea C, Vigouroux T, Karam J, et al.Horner syndrome in children: a clinical condition with serious underlying disease.Neuropediatrics. 2016;47(4):268-72. doi:10.1055/s-0036-1584085
NIH Genetics Home Reference.Horner syndrome.
Horner’s syndrome: genetic and rare diseases information center (GARD) – an NCATS Program. National Center for Advancing Translational Sciences (NIH).
NIH. Genetics Home Reference.Horner Syndrome.
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