What is it headshaking?
Headshaking is characterised by a sharp, usually vertical movement of the head, although rotatory or horizontal headshaking is occasionally seen. This has been described as a rapid downward jerk of the nose followed by an upwards fling of the nose. Affected horses may also experience nasal irritation leading to rubbing of the face and self-trauma.
What causes headshaking?
Headshaking is generally thought to occur due to some form of irritation similar to hay fever. This can be due to plant pollens / dust (allergic rhinitis), flies or even certain weather conditions i.e., sunlight (photic headshaking), which causes irritation to the sensitive mucous membranes that line the nasal passages. Some cases are seasonal and some horses only headshake when ridden, often made worse on hot, bright sunny days. As knowledge of this condition has developed, it is likely horses who headshake suffer from what is termed Trigeminal Neuralgia. The trigeminal nerve is one of the cranial (head) nerves and has three divisions (rather like the branches of a tree) and contains both motor (movement) and sensory (feeling) responses. The three divisions are: Ophthalmic (the area of the temples, eyes, and nose), Maxillary (the mouth and lower cheeks) and Mandibular (the jaw). If any of these three divisions become inflamed, the horse may experience an uncomfortable sensation, hypersensitivity or even pain. This can lead to headshaking, nose twitching or facing rubbing to remove this sensation. This can affect either one or both sides of the face.
How can I distinguish headshaking from other conditions?
How is headshaking diagnosed?
Before you jump to the conclusion that your head shaker has trigeminal neuropathy, work with your veterinarian to rule out other medical or environmental reasons for the behaviour. Unfortunately, headshaking can’t be cured, but often it can be managed by identifying the trigger factor. Observing the horse’s behaviour, both in the stable and when ridden, is important. This will allow problems with the tack or behaviour to be evaluated and excluded. It is often useful to observe the horse worked on different days and in different environmental conditions to enable potential trigger factors to be established. In addition, appropriate diagnostic tests should include:
If the classic clinical signs are present and these diagnostic tests are within normal limits, a diagnosis of idiopathic headshaking is often made.
What can I do to help my horse that is headshaking?