Headshaking in horses: causes and management

What exactly is headshaking?

In headshaking syndrome, a horse makes involuntary, sudden head movements — usually vertical, sometimes lateral or in circles. This is emphatically not a behavioural problem or disobedience. The movements are caused by hypersensitivity or overstimulation of the trigeminal nerve, the large nerve responsible for sensation in the head and nose. Horses often rub their nose along the ground or their front leg, as if trying to brush away an insect. Symptoms can be seasonal — peaking in spring and summer — or present year-round. Warmbloods between 7 and 10 years old are more frequently affected than other types of horses.

Possible causes at a glance

There is rarely a single cause. Factors that can trigger or worsen headshaking include:

• Trigeminal neuropathy: overstimulation of the facial nerve, often triggered by light (phototrigeminal syndrome)
• Allergies to pollen, dust, or mould spores
• Dental problems, such as sharp points or a poorly fitting bit
• Ear or sinus inflammation
• Issues with the headcollar or the fit of the bit

How does the vet make a diagnosis?

A vet establishes a diagnosis step by step. First, a full clinical examination is carried out: teeth, ears, head, and neck. This is often followed by a ridden test to determine whether symptoms increase during riding. If trigeminal neuropathy is suspected, the vet may perform a so-called nose-mask test: a fine gauze hood that covers the nose. In 70% of horses with phototrigeminal syndrome, symptoms noticeably decrease with this. Blood tests, X-rays of the sinuses, or an endoscopy can provide additional information. Record in the EquiSight horse profile when symptoms occur — time of day, weather, activity — so you can show the vet a clear pattern.

Treatment options and aids

• Nose net or fringe: directly relieves symptoms in many horses by reducing stimulation of the nasal nerve
• Light filter or visor: helps horses for which sunlight is the main trigger
• Melatonin: a daily dose of 12 mg can reduce symptoms of seasonal headshaking by 30–60%
• Magnesium supplementation: adding 5–10 grams per day is rated positively by some owners
• Percutaneous electrical nerve stimulation (PENS): a new treatment that 'resets' the trigeminal nerve, with good results in 60–70% of treated horses

Adjustments to daily management

Alongside medical treatment, you can adapt the environment to reduce triggers. Ride preferably early in the morning or late in the evening when pollen levels are low. Use a fine-mesh fly rug with ear covers and a nose fringe. Choose a bitless bridle or experiment with a softer, well-fitting bit. Some horses also respond positively to an increase in roughage intake and a reduction in starch. Use the EquiSight calendar to plan rides on days with a low pollen alert and to keep track of your findings. After making adjustments, you can ask EquiCoach to analyse patterns in your notes and help you identify the most effective combination of measures.

When is stopping riding the best choice?

For some horses, headshaking syndrome is so severe that riding is dangerous — for the horse and the rider alike. If a horse shakes more than two to three times per minute during riding and does not respond to multiple treatments, it is wise to assess together with your vet whether turnout in a quiet paddock is a more humane alternative. This is not a failure: it is the best possible care. Document all treatments, responses, and periods of improvement or deterioration in the horse profile so that future vets immediately have a complete picture.