If your young horse is unhappy when you touch his head, it could be that he has an 'ear tooth'. But what is an ear tooth, how do you know if you horse has one and what can your vet do to help?

What is an 'ear tooth'?

The correct veterinary term for this condition is temporal teratoma or dentigerous cyst. The condition is caused when one of the horse's molar teeth grows in the wrong direction, up towards the ear. The growth develops into a cyst or sac that contains part or all of a tooth or other dental tissue.

What are the symptoms of an 'ear tooth'?

Ear teeth occur in young horses as their adult teeth grow, although the condition can be found in older animals if it goes undiagnosed for a long period of time.

The horse will be in extreme discomfort and will be very reluctant to allow his handler to touch his face and head. This can make putting on a bridle or headcollar very difficult and often leads to affected horses becoming habitually head-shy.

When the horse is ridden, he will continually shake his head and may also carry it to one side in an attempt to alleviate the pain caused by pressure from the bridle's headstall. 

Many ear teeth present no external symptoms initially, which is why diagnosis can be so difficult.  However, ear teeth more commonly appear near the base of the horse's ear, presenting as a hard swelling.  Sometimes the cyst will begin to leak a thick, white fluid.

How can your vet help?

Because ear teeth are true cysts, they have a lining.  The lining produces exudate and the cyst must therefore be removed to prevent drainage.  Fortunately, dentigerous cysts are regarded as a developmental anomaly, rather than tumours and are not cancerous.

Your vet will recommend radiographs and MRI imagery to make a positive diagnosis.  Your horse will then require hospitalisation in order to have the cyst surgically removed.

Recovery is complete within a few weeks, and the horse should be able to return to work within a month or so. There may be some nerve damage to the horse's ear following surgery, depending on the location of the cyst. However, this will not cause any discomfort or affect the horse's quality of life.

If the condition has been longstanding, the horse will probably continue to be head-shy, even after the pain has gone. However, with patience and time, he may get over this.

If your young horse becomes head-shy and begins to shake his head or carry it to one side when ridden, he could have a dentigerous cyst. Don't leave your horse to suffer in silence; schedule an appointment with a veterinarian.