What Is Horner Syndrome?

Horner’s syndrome or oculosympathetic palsy is a disorder that affects the eye and the tissue surrounding it on one side of the face. The sympathetic nerves that arise from the spinal cord and enter the facial area are found to be damaged in this rare disorder, giving rise to problems with the eye and eyelid movement. It can affect any age group, though in 5% of cases it appears as a birth defect.1

Identifying Horner’s Syndrome

The symptoms of Horner’s are unilateral and appear only on one side of the face. They include:

  • Droopy upper eyelid (ptosis) on the side of the face that is affected
  • A highly constricted pupil on this side (miosis)
  • Unequal sizes of the eye pupils (anisocoria; caused by miosis in one eye)
  • Reduced or no sweating in the affected side of the face (anhidrosis)
  • Eyeball sunken into the bone cavity (enophthalmos)

If Horner’s syndrome sets in before the age of 2, the irises of both eyes will be of different colors (with the side that is affected having a lighter colored iris). This is called heterochromia iridis. In a preliminary investigation, the doctor will check for these signs. Another test that is often conducted involves pinching portions of one side of the neck or face. When done by a trained practitioner, this stimulus causes the pupil on that side of the face to dilate rapidly in healthy people. In those with Horner’s syndrome, this response – called the ciliospinal reflex – is absent.2 Once these signs have been identified, a medical imaging technique is often used over the affected region to understand what may be causing the problem. Horner’s syndrome by itself doesn’t harm the eye or your general health. But what you need to look out for is the underlying cause for Horner’s – this can pose a threat to your health and even be life-threatening.

Causes Of Horner’s Syndrome

Horner’s syndrome occurs mainly because of a loss of activity in one part of the sympathetic nervous system. This loss of activity can happen due to a variety of reasons.

  • Trauma and Cancers: Any injury to the spinal region, especially in newborns, can cause Horner’s syndrome. Insect bites, snake bites, blunt trauma to the neck can also be triggers. Tumors in the neck or chest cavity, and specifically cancers such as neuroblastoma and Pancoast cancer, can cause Horner’s. Lesions in the brain, brain stem, or upper spinal cord, neck or eye area, and inflammation of the neck lymph nodes can also cause the facial sympathetic nerves to be damaged and result in Horner’s syndrome.3
  • Genetic Causes: Very rarely, Horner’s syndrome can be passed on to a person from the immediate family. In these people, the inheritance pattern is dominant, which means that even if just one parent has the defective gene, it can be passed on to the child. Further research will help clarify the role of specific genes in the process.4
  • Other Causes: Complications or trauma resulting from surgery in the neck or upper spinal cord, inner ear infections, aneurysms and other blood clots, vascular diseases,5 and goiter are some other causes of Horner’s syndrome.6

Treating Horner’s Syndrome

There is no treatment for the disorder itself. The focus instead is on identifying the underlying cause and addressing it. If the cause is cancer, it can be treated using conventional methods such as chemotherapy and radiation or surgery. If the cause is vascular in nature, doctors identify the source of blockage of blood supply and work to resolve it. If the cause is genetic, a regime may be suggested to manage specific symptoms.

Neuroblastoma (brain cancer) is one major cause of Horner’s syndrome, particularly in children. A novel approach to treating malignant neuroblastoma is being tried, wherein targeted therapy kills cancer cells using the body’s natural immune response.7 Turmeric, a known anti-cancer agent, when used along with chemotherapy, has also shown promise in treating brain cancer.8 When lesions appear on the sympathetic nerves and cause Horner’s syndrome, the condition itself is usually irreversible.


However, once the underlying causes are addressed, the patient has a significantly improved quality of life. However, when Horner’s syndrome is the result of compression of the same nerves and no permanent damage has been done, as in cases of Hashimoto’s Disease of the thyroid gland,9 relieving the nerve compression can reverse the symptoms of Horner’s syndrome.