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How Dangerous Is Horner’s Syndrome & Is It Contagious?

Horner’s Syndrome is a medical condition developed due to disruption in the sympathetic nerve pathway. It is named after Dr. Johann Friedrich Horner, who concluded that this Syndrome is caused by this disruption. It is caused by injury to the sympathetic nerve pathway due to stroke, spinal trauma, etc. It usually affects one side of the face.

Its symptoms appear in one of the eyes. Its symptoms involve ptosis, small pupil, reduced sweating on one of the sides of the face. It usually does not affect the vision of the person. It is diagnosed by a cocaine drop test, paredrine test, neurological examination, and imaging tests such as X-ray, CT scan, and MRI scan.

How Dangerous Is Horner’s Syndrome?

Horner’s Syndrome is a rare syndrome caused due to an alteration in the sympathetic neuro-pathway. This pathway is disrupted from the brain to eye and face appearing on one of the sides of the body. It usually appears after stroke, tumor, or spinal cord injury.(5) It is found that approximately 60% of cases have known causes, and the other 40% are idiopathic or without any identified causes. The main characteristic features of this Syndrome involve ptosis of the eyelids (drooping eyelids) and ipsilateral (one side) miosis of the pupil.(1)

It is observed that Horner Syndrome affects only one of the sides of the face. It is represented by following signs and symptoms-

  • A small pupil (miosis)
  • There is a noticeable difference in the size of the pupil between both the eyes (anisocoria)
  • Drooping of one of the upper eyelids (Ptosis)
  • Reduced opening (dilation) of the involved pupil in the dim light
  • Sunken eyes
  • Upside –down ptosis (Slight elevation of the lower lid)

Reduced or no perspiration on one or either side of the face sometimes on the isolated skin patch on the involved side (anhidrosis)

In many cases, only ptosis and anhidrosis are present which is sometimes difficult to detect. In children, some additional symptoms are represented, such as light-colored Iris in the involved eyes below the age of one-year-old and reduced redness or flushing on this side, which should appear after physical exertion, heat, or emotional reactions.(5)

Horner’s Syndrome is considered of deep concern because its many possible causes are either severe or possibly life-threatening.(1) Though symptoms of this Syndrome are not dangerous, it may indicate a more severe health problem such as stroke, spinal cord or brain injury, etc.(3)

There are some severe symptoms of Horner’s Syndrome that should be treated in time. These severe symptoms are listed below:

  • Dizziness
  • Vision problems
  • Sudden and severe neck pain or a headache
  • Weak muscles or loss of ability to control the muscle movements(2)

Is Horner’s Syndrome Contagious?

Let us know the causes to see if this syndrome is contagious.

Lesion Or Injury To The Cervical Chain- Horner’s syndrome is caused by an accident or traumatic injury.

Trauma To The Neck- any injury to the neck, such as severe whiplash can induce this condition.

Infection – middle ear infections can cause injury to the sympathetic nerves supplying the face and eyes.

Tumor Developed In The Anterior Part Of The Lung- Lung cancer is linked with this condition. Some clinical studies state that it is one of the common causes of this condition.

  • Migraine Or Headaches- appearing in the form of clusters may also be one of the risk factors of this Syndrome.
  • Stroke Or Cerebrovascular Accident- researchers believe that Aneurysm can induce this condition.(4)

These causes indicate that this Syndrome is not a contagious disease.


Horner’s Syndrome is not a dangerous condition, as its symptoms do not itself cause serious health problems. It usually indicates its severe or life-threatening underlying causes such as stroke, tumor, or injury to the brain or spinal cord. It is not a contagious disease.


Also Read:

Team PainAssist
Team PainAssist
Written, Edited or Reviewed By: Team PainAssist, Pain Assist Inc. This article does not provide medical advice. See disclaimer
Last Modified On:May 2, 2020

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