Horner’s syndrome is a condition involving the sympathetic nerves of the face. These nerves run to the face from the hypothalamus in the brain via the spinal cord. Damage to the nerve fibers can interrupt their function and cause a specific set of symptoms.

Though a rare condition, Horner’s syndrome has many possible causes. According to the Genetic and Rare Diseases Information Center, one of these is trauma to the neck and/or shoulder during birth. If you observe symptoms such as the following in your newborn baby, consult with your doctor right away.


Most of the common symptoms of Horner’s syndrome involve the eyes. Anhidrosis, that is, decreased or absent perspiration, is one notable exception. This affects the face and is typically only present on one side.

Heterochromia iridium

This is a symptom that is frequently present in babies with Horner’s syndrome but occurs less frequently in cases acquired later in life. The iris is the colored part of the eye. Horner’s syndrome causes a deficiency of the pigment of one of the irises. As a result, the eyes may be two different colors.

Miosis and ptosis

The pupils have the ability to dilate (open up) and constrict (close down) to control the amount of light that enters the eye. Horner’s syndrome can cause miosis, i.e., abnormal constriction of the pupil. The disruption of the nerve function can also cause ptosis, which is a persistent drooping of the eyelid.

Your doctor may refer your baby to an ophthalmologist to assess for Horner’s syndrome. The ophthalmologist may perform special eye tests to make a definitive diagnosis.