15/10/2026
Trigeminal-mediated headshaking in horses is a neuropathic pain condition in which the trigeminal nerve, responsible for sensation in the face and muzzle, becomes abnormally sensitive or overactive.
This causes episodes of sudden, involuntary head tossing, flicking, or jerking, often accompanied by muzzle rubbing, snorting, or striking at the face with the forelimbs. Signs may worsen during exercise or exposure to sunlight, wind, or other stimuli.
The condition is thought to result from lowered activation thresholds in the trigeminal nerve, causing normally harmless stimuli to trigger pain similar to electric shocks or burning sensations.
It is a diagnosis of exclusion: dental, sinus, ear, ophthalmic, and other underlying causes of headshaking should first be investigated, of which his caring owner has completed.
EPNS (electropercutaneous neuromodulation stimulation) is a technique that uses electrical stimulation delivered through the skin via specialised electrodes or needles to influence the activity of peripheral nerves.
# # # How might it help trigeminal-mediated headshaking in horses?
Trigeminal-mediated headshaking is associated with abnormal sensitivity of the trigeminal nerve, which transmits sensory information from the face and muzzle to the brain. Affected horses may experience episodes of facial pain, often described as similar to an electric shock or burning sensation.
EPNS aims to modulate nerve activity and reduce abnormal pain signalling, potentially decreasing the frequency or severity of headshaking episodes.
# # # What does the evidence show?
A multicentre study of 168 horses treated with EquiPENS, a form of percutaneous electrical nerve stimulation (PENS), reported that 53% of horses with recorded follow-up entered remission after the initial treatment course. The median recorded remission period was 9.5 weeks. However, the study had no control group, and outcomes were assessed by owners, so the results should be interpreted cautiously.
In practical terms: EPNS/PENS is a minimally invasive treatment option that may provide relief for horses with trigeminal-mediated headshaking. It is not a guaranteed cure, and the precise mechanism by which it works remains incompletely understood. Treatment should be performed by a suitably trained veterinary professional.
