HEADSHAKING in horses is not a common problem but when it occurs it can be very frustrating for horse and rider and it can be difficult to cure.

In my routine work as a vet I would only see headshaking cases once or twice a year. The most common age group is eight to 10 years and it is seen more in males than in females.

WHAT HAPPENS?

Headshaking is most commonly seen in the spring/summer. It is most often seen when the horse is being ridden and less often at rest. The symptoms often appear suddenly. The horse shakes or flicks its head mainly in a vertical motion and less often in a horizontal motion.

The movement is sudden and unpredictable. The horse often snorts as if there is a fly in its nose and often tries to rub its nose and muzzle on surfaces to get relief. The horse appears to be stressed and the movements suggest that the horse is experiencing some irritation or pain.

Many cases appear to be more symptomatic in strong sunlight and less so in darkness. When a horse behaves like this it can be very difficult to ride and in some severe cases may even be unrideable.

In case the symptoms are due to incompatibility between horse and rider then a more experienced rider should ride the horse to check if the symptoms are consistent.

It is possible that a horse with a poor temperament may show behaviour like headshaking.

CAUSES/DIAGNOSIS

Headshaking has many possible causes. If your horse presents with symptoms of headshaking your vet will need to perform a thorough clinical examination to see if they can find the reason for the problem.

The vet will take a step by step approach to their examination. Diagnosing the cause can be a challenge.

When a vet is presented with a case of headshaking they have to check out any likely cause of irritation/pain mainly in the head area of the horse but also elsewhere in the body like the back.

The initial examination involves examination of the face/eyes/ears/mouth/neck/back.

If this initial examination does not reveal the cause then X-rays of the head and an endoscopic exam of the inside of the head are the next steps.

The above examinations often reveal causes such as:

  • Sinus infections or tumours
  • Dental problems
  • Eye problems
  • Ear problems
  • Neck pain
  • Arthritis of joints in the head region
  • Growths in or irritations of the nasal chambers

    • If a cause is found then it can be treated and resolution may be possible. However in many cases thorough investigation proves fruitless and we have to consider other possible causes. Other possible causes include:

    Neuropathy of the trigeminal nerve: The trigeminal nerve supplies sensory perception to the face and it is thought that damage to that nerve (neuropathy) can cause unusual sensation in the face causing the horse to react suddenly and unpredictably. Under hospital conditions it is possible to perform delicate facial nerve blocks to try to prove if the trigeminal nerve is involved.

    Allergies: The bodies reaction to certain allergies may cause irritation in the internal lining of the nasal chambers again causing severe irritation. If this is proven to be the root cause then these horses may respond to anti-allergy treatment such as anti-histamines or steroids.

    Extreme sensitivity to sunlight: Some horses eyes are very light sensitive and this can cause unusual reactions.

    TREATMENT

    As has been mentioned already if a very specific cause is found during the veterinary examination, for example an eye problem, then specific treatment can be commenced for that condition.

    In the cases that do not have an obvious cause and where it may be likely that there is some involvement of the trigeminal nerve (neuralgia) then using a face net which covers the nose and nostrils is worth trying.

    It is thought that the face net somehow reduces the sensitivity of the nerve. One theory is that it is like the human equivalent to knocking your elbow. It hurts but if you massage the area the pain perception reduces.

    It is thought that the nose net stimulates the trigeminal nerve and there are claims of up to 70% relief in 25% of the cases where nets were used. Face nets are available commercially and are not expensive.

    In cases where it is felt that allergies are involved vets often prescribe antihistamines or steroids for treatment. If the horse is extremely sensitive to light then it can be kept indoors more often and ridden in less strong sunshine.

    PROGNOSIS

    The condition carries a guarded prognosis. Some cases may be diagnosable and treatable. However, many are not.

    Denis Doyle MVB MRCVS is a veterinary surgeon in Wicklow town and is a member of the Equine Group of Veterinary Ireland

    Email: hq@vetireland.ie

    Telephone: 01-4577976