What is a normal ear like?
The normal ear canal and ear flap are lined with smooth pale pink skin. The ear canal is usually empty and conducts sound down to the ear drum. Some breeds of dog have hairy ear canals.
The canal lining produces a small amount of wax that gradually moves up the ear, removing any dust or debris with it. The normal ear does not have any unpleasant smell or any discharge. The middle and inner parts of the ear, concerned with hearing and balance, are located within the skull.
What is otitis externa?
The most common ear disease seen in dogs is otitis externa (inflammation or infection of the ear canal, which may include the ear flap and the ear drum). Otitis externa is painful.
The major signs are:
- Head shaking or scratching of the ear.
- The ear may smell.
- There may be discharge, either wax or pus.
- The skin of the ear may look pink or red.
- Occasionally the ear is so painful the dog may be unable to shake their head. They may be very still and cry out.
Otitis externa can be caused by inflammation or by infection with bacteria, fungi (yeasts) or mites. The predisposing causes for otitis externa include:
- Narrow ear canals, due to the breed of dog e.g. Sharpei, or due to chronic inflammation and thickening of the skin lining the ear canal.
- Hairy ear canals, usually seen in certain breeds. Hairs and narrowing of the canals make the ear canals more humid and therefore more prone to infections.
- Dangling ear flaps, usually seen in breeds such as Bassett Hounds and Spaniels. The ear flaps cover the entrance to the ear canals so that air cannot flow freely into the ear, again making the ear canals more humid.
- Ear mites, most commonly seen in puppies.
- Allergic skin disease or other diseases affecting the whole skin.
- Foreign bodies, such as grass seeds, more common in summer.
- Swimming, especially in dirty water.
Acute and chronic otitis externa
Otitis externa can either be acute, of sudden or recent onset, chronic, long lasting with permanent damage to the ear. Damage can include ruptured ear drum, middle ear infection, thickening of the skin lining the ear and mineralisation (hardening) of the cartilage support of the ear canal.
Acute disease usually responds well to medical treatment but if it is neglected, or keeps recurring, chronic changes may develop. Chronic disease may not respond to medical treatment and surgery may be needed.
As long as the patient is well behaved and not in too much pain, the best way of seeing the ear canal is for a vet to look down the ear with an auriscope (special nozzle attached to a torch). The vet can assess the health of the ear flap, ear canal and ear drum.
In cases where scoping is not possible, the patient may need to be examined under general anaesthetic. In some cases, a general anaesthetic may be advised so the ears can be syringed clean or to allow removal of a foreign body.
Sometimes a smear of wax or pus from the ear is examined under a microscope to tell what type of inflammation or infection is present. In some severe or ongoing cases, a swab of the discharge is sent for culture to a laboratory, so the type of bacteria or fungus causing the problem can be identified and appropriate medication can be prescribed.
In acute otitis, ear drops containing some combination of steroid, antibiotic, antiparasitic and antifungal agents are often used. Sometimes steroid injections or tablets are given to reduce inflammation and in some cases, antibiotic tablets may be dispensed.
A follow up examination is done 1-2 weeks later so that the vet can see whether the whole of the outer ear is now healthy or whether further management is needed. If things are going well, regular use of ear cleaning drops is usually advised to keep the ear clean and healthy.
If the underlying problem is a generalised skin disease, management of the skin problem will help control the ear problem. Long term use of ear drops to remove wax or ear drops containing steroids may be necessary.
If the ear is beyond medical management and there are permanent structural changes or chronic pain, surgery may be used to salvage the situation. For chronically painful ears surgery to remove the whole of the ear canal can provide relief.
Otitis externa is a painful condition that needs to be treated early and completely to prevent permanent damage to the ear. Sometimes ongoing treatment is needed to keep things under control.