Horner’s Syndrome Symptoms

Horner’s syndrome is a nerve disorder that affects a person’s eye. It causes the eye to droop, constricts the pupil, and reduces sweating in the affected area. Horner’s syndrome can occur on its own or as a consequence of other diseases or conditions, including birth injuries caused by trauma during delivery.

Horner’s Syndrome: Basic Facts

Horner’s syndrome is a disorder that affects the sympathetic nervous system. It is a combination of indications and symptoms linked to damage to the nerves that connect the brain to the eyes. Also known as oculosympathetic palsy, Horner syndrome, or Claude Bernard-Horner syndrome, it may occur independently or as a result of another condition, such as a tumor, middle ear infection, a stroke, or syringomyelia (a cavity or cyst in the spinal column).

Horner’s syndrome can also be caused by trauma to the neck. It can develop in adults and children. In neonatal cases, Horner’s syndrome may sometimes be a result of something congenital. However, a birth injury to the sympathetic nervous system during delivery can result in an occurrence of Horner’s syndrome in a newborn infant, and accounts for hundreds of Horner’s Sydrome cases each year in the United States.


Per the Mayo Clinic, Horner’s syndrome symptoms generally manifests itself on one side of the infant’s face. If, for instance, the sympathetic nerve on the left side of the baby’s face has a lesion or a compression, Horner’s syndrome affects the area around the corresponding eye. The syndrome’s most common symptoms include:

  • Drooping of the upper eyelid caused by lack of stimulation from a damaged nerve to Muller’s muscle (partial ptosis)
  • Small elevation of the lower eyelid (upside down ptsosis)
  • Lessened or no perspiration on the affected side of the face (anhidrosis)
  • A persistently constricted pupil (miosis)
  • Noticeable size difference between the affected pupil and the unaffected one (anisocoria)
  • The appearance that the affected eye is sunk in (enophthalmos)
  • Affected pupil dilates either slowly or slightly in dim light (loss of ciliospinal reflex)
  • Bloodshot conjunctiva (lining of the eye that covers the sclera or “white of the eye”)

In children, Horner’s syndrome symptoms may also include:

  • Flushing (absence of redness) of the affected side of the face, caused by damage to the nerves that control blood flow to the skin
  • Iris remains blue-gray as it is at birth in cases where the syndrome occurs at birth

The Mayo Clinic suggests that symptoms such as ptosis and anhidrosis are subtle and not easy to detect.

Common Causes of Horner’s Syndrome

Although Horner’s syndrome may occur on its own, it usually is a result of other medical conditions affecting the sympathetic nervous system. The most common triggers of Hunter’s syndrome include:

  • Cluster headaches
  • Damage to the carotid artery
  • Damage to the aorta
  • Damage to the jugular vein
  • Migraines
  • Schwannoma (tumor in the myelin sheath)
  • Thoracic surgery
  • Lung cancer
  • Traumatic injuries
  • Goiter
  • Neck trauma
  • Myelin loss caused by various diseases
  • Tumors

In children, Horner’s syndrome can be caused by:

  • Injury to the neck and/or shoulders during delivery
  • Congenital defect of the aorta
  • Neuroblastoma (tumor of the hormonal and nervous system)

In some instances, it is not possible to trace Horner’s syndrome to a specific cause.

Complications and Treatment Options

Horner’s syndrome does not cause any complications of its own. However, when it is triggered by another disease, such as brachial plexus, there will be complications from either the underlying cause or its treatment.  In addition, although there are no treatment options specifically for Horner’s Syndrome, treatment for the underlying cause of the condition usually helps to clear it up. In instances in which no underlying issue is found, Horner’s Syndrome almost always clears up without much incidence.