Cicatrix Syndrome in Horses

A cicatrix is a scar resulting from formation and contraction of fibrous tissue in a wound. In horses, nasopharyngeal cicatrix syndrome (NCS) refers to a condition in which the larynx and throat in a horse’s upper airways become inflamed and irritated due to a factor that has not yet been identified.

Over time, the inflammation can lead to scarring that narrows and constricts the airway to a degree that sometimes requires a permanent tracheostomy to allow the horse to breathe. NCS has been reported in Texas and the panhandle of Florida, but not in more northerly regions.

Based on a study of 121 normal horses and an equal number of horses affected with NCS, researchers at Texas A&M University found that the condition was more common in older horses and those that were turned out in pastures. Diagnosis was most frequent during the summer months. These risk factors suggest that NCS may be caused by long-term exposure to an environmental irritant or infective agent such as mold spores, plant pollen, insects, or bacteria, all of which are naturally found in summer pasture. Identifying the exact cause will be challenging, and eliminating it from the environment may be almost impossible.