Is my horse a Headshaker?

 
Has your horse suddenly started behaving like a heavy metal music fan shaking his head like a Deep Purple devotee whenever you ride? If so it is possible that hes suffering from headshaking a frustrating and distressing condition for both horse and rider not least because its notoriously difficult to establish a cause and find a successful treatment.
What is headshaking? 
The term headshaking has been used as a loose descriptive term encompassing any horse that shakes its head for any reason.  For some horses this may be a painful or behavioural response to an unpleasant stimuli such as badly fitting tack flies a foreign body in the nose or even neck or back pain.  However for the vast majority of horses headshaking is now understood to be a manifestation of some form of facial pain. Sometimes the cause of pain can be identified for example a tooth or sinus infection however in a large number of horses physical changes cannot be found and these are the ones we classify as idiopathic headshakers.

For most of these horses headshaking behavior is thought to be due to pain in the trigeminal nerve a syndrome now most correctly known as trigeminalmediated headshaking.  This is a very distressing and difficult condition which can result in the horse becoming unrideable or in severe cases resulting in euthanasia on humane grounds.
Whilst headshaking from an underlying cause may be in any direction the headshaking seen in trigeminalmediated headshaking is often very characteristic with repetitive and apparently involuntary vertical movements of the head which may become dangerous. The horse may try to rub its face strike at the nose with a foreleg or attempt to hide the nose. It may be accompanied by snorting and nasal discharge. While some signs may be displayed when the horse is at rest the condition usually becomes most apparent during exercise. The signs may be intermittent or persistent seasonal or nonseasonal.  It is very upsetting for the horse and for everyone involved in its care.
What causes headshaking? 
Identifiable causes of headshaking behaviour include anything that causes pain and irritation to the face particularly the teeth and sinuses or even the neck back and in rare cases lameness. It is important to thoroughly rule out and treat any underlying cause early in the disease process. Unfortunately in many cases a cause cannot be identified and a diagnosis of idiopathic headshaking is made.
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