Nasopharyngeal Cicatrix Syndrome (NCS) is an upper respiratory tract condition of horses in which the pharynx becomes inflamed and irritated. Over time, the inflammation can lead to scarring that narrows and constricts the airway, restricting air passage in affected horses. Some horses require surgery in order to breath.
Clinical signs of NCS in horses are related to the respiratory system, such as coughing, nasal discharge, exercise intolerance, flared nostrils, respiratory noise, extended head and neck, and increased heart rate. Affected horses may have one or more of these signs and some have no apparent symptoms whatsoever.
The cause of NCS in horses is unknown, however it is thought to be associated with exposure to an environmental irritant in horse pastures. Treatment is generally unrewarding, as none of the attempted therapies have proven to be of much success, other than removal of affected horses from contaminated pastures may help stop exposure to the irritant and reduce the development of scar formation to the pharynx.