Photic Headshaking Syndrome

Cindy Hale

Head Shake

Horses shake and toss their heads for a variety of reasons, including minor annoyances like a forelock snagged on a browband, tooth and ear pain, and training issues. But photic headshaking syndrome produces a very unique behavior. The horse spontaneously jerks or flips its head without any obvious stimuli. The repetitive action seems involuntary, much like an uncontrollable tic in a human.

Horses thought to suffer from photic headshaking syndrome deserve a complete evaluation from an equine vet to rule out any other causes. But once the diagnosis has been made, it can be a frustrating undertaking to extinguish the behavior. Because bouts of sneezing can accompany the onset of the behavior, antihistamines are often tried at first, just in case the horse is suffering from a seasonal allergy. Other treatment options range from oral medications to surgical procedures on facial nerves. Anecdotally, some horse owners have found improvement by keeping a fly mask on their horse as a sort of sunscreen. Indeed, there appears to be a relationship between sunlight and the headshaking behavior, hence the word photic (meaning “light”) in the malady’s name.

With some lucky horses, the compulsive headshaking spontaneously disappears with a change of seasons. Unfortunately, there are other horses whose headshaking progresses to a year-round obsession. Their headshaking behavior exceeds being a nuisance and renders them virtually unrideable. With a dedicated equine vet and a patient owner, however, most horses diagnosed with photic headshaking syndrome can be made comfortable and remain useful.


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