Ear Infection (External Otitis)
External otitis is an infection of the ear canal. Ear problems are estimated to affect up to 20% of all dogs and up to 7% of cats. The ear canals are delicate structures and are easily infected. 80% of infections occur in breeds with long, dropped ears.
Signs of external otitis are head shaking and scratching and rubbing at the affected ear. The ear is painful, and the dog often tilts or carries her head down on the painful side and cries or whines when the ear is touched.
Ceruminous otitis occurs with primary seborrhea. There is an extensive buildup of oily, yellowish wax in the ear canals, which provides an excellent medium for bacteria and yeast. Treatment is directed toward control of the seborrhea. Regularly cleaning the ear canal may be necessary until this problem is controlled.
Bacterial Otitis in its acute form, is usually caused by Staphylococci. The discharge is moist and light brown. Chronic infections are usually caused by Proteus or Pseudomonas bacteria. The discharge is generally yellow or green, although there are exceptions. More than one species of bacteria may be involved, which complicates the antibiotic treatment.
Yeast or fungal infections may follow antibiotic treatment of bacterial otitis. Yeast infections also occur commonly in dogs suffering from atopic dermatitis, food hypersensitive dermatitis, and seborrheic skin diseases. A brown, waxy discharge with a rancid odor is sometimes seen, or a very red, inflamed, moist ear with minimal discharge. These infections tend to persist until the underlying disease is controlled.
Many factors contribute to the development of external otitis. Clean, dry ears stay healthy. But water, soap, excess wax, or foreign objects like grass seeds or wads of hair can lead to infections.
Most dos ear problems are caused by an overgrowth of yeast, a kind of fungus that's normally found inside the ear canal. But the when yeast grows too rapidly, the ears get hot and inflamed and look kind of "goopy".
Some breeds (such as the Chinese Shar-Pei) are predisposed to the condition because of narrow or stenotic (an abnormal narrowing of a structure) ear canals. Other breeds may be predisposed because they have an abundance of hair that blocks the circulation of air.
Many dogs with allergic skin diseases, particularly canine atopy and food hypersensitivity dermatitis, are predisposed to ear infections as part of the generalized skin response. Similarly, dogs with primary and secondary seborrhea often have ear canal involvement characterized by a buildup of yellowish oily wax that provides an excellent medium for bacterial growth.
Iatrogenic (induced inadvertently by medical treatment or diagnostic procedures) causes of infection include using cotton - tipped applicators to clean the deep recesses of the ears, allowing water to get into ears during bathing, excessive and improper cleaning of the ears, and a grooming routine that calls for plucking or clipping hair in the external ear canals.
Veterinary examination of the deep portions of the ear canal using an otoscope is the most important step in making the diagnosis and planning treatment.
Otoscopic examination cannot be attempted if the canal is dirty and filled with wax and purulent debris. First the ear must be cleaned. This may require sedation or anesthesia.
An examination reveals redness and swelling of the skin folds. There is usually a waxy or purulent (puss like) discharge with a bad odor. Hearing can be affected.
It is essential to know whether the eardrums are intact, since it is not safe to medicate the ears with certain medications if the drums are perforated. It is also important to be sure the problem is not caused by a foreign body or tumor. A specimen of waxy material is taken with a cotton tipped applicator, rolled onto a glass slide, and examined under the microscope looking for bacteria, yeast, ear mites, and any other predisposing factors. Your vet may need to do a culture and sensitivity test on the discharge, especially if this is a recurring problem. A correct and definite diagnosis of the cause helps to determine the most appropriate and best treatment.
Because external ear infections often progress to the middle ear, it is extremely important to take your dog to a veterinarian as soon as you suspect a serious ear problem.
The first step in treatment is to clean and dry the ear canals. This requires ear-cleaning solutions (irrigation), a syringe, an ear curette (ear pick), and cotton balls. It should be done at the veterinary clinic. Cleaning creates a less favorable environment for bacteria to grow and allows the medication to treat the surface of the ear canal. Medication can't penetrate the debris in a dirty ear.
A dark brown to black waxy material that is runny and smells rancid is probably a yeast overgrowth. Yeast and fungal infections are very common in dogs but less often diagnosed in cats. Return your pet's ears to their normal acidic pH with a 50/50 vinegar and water solution twice a day. Put this mixture in a spray bottle, lift the ear flap, and spritz the ears with the solution. Then wipe out the portion of the ear that you can see with a cotton ball. If you don't see improvement in 24 - 48 hours, take him to the vet.
Follow up care at home involves medicating the ear with a preparation prescribed by your vet. If the ear continues to produce wax and exudate, a cleansing and flushing solution such as Oti-Clens or Epi-Otic, and/or a drying solution such as ClearX or Panodry, may be recommended. These solutions are used immediately before medicating the ear with an anitbiotic or anti-fungal medication. Topical and/or oral corticosteroids may be recommended to control pain and decrease swelling and inflammation. Some dogs may need oral antibiotics ans well for severe infections.
Bacterial infections that continue to progress produce thickening and narrowing of the ear canal and chronic pain. These ears are difficult to clean and treat. As a last resort, your vet may advise a surgical procedure called an ear resection that re-establishes air circulation and promotes drainage.
Ear maintenance is your best preventative to this condition. Inspect and clean your pets ears on a regular basis (once per week should suffice). Ask your vet or a professional pet groomer to show you how to do this correctly.
If you notice a foul odor coming from your pets ears or she is often busy scratching and rubbing them, take her in for a checkup.
Many ear infections begin with a common food allergy reaction. The allergy triggers itching of the ears, and the itching of the ears leads to an ear infection due to the un-sanitary pet nails digging into the ear repeatedly. Look for common allergens in your pet food such as corn (and corn by products), wheat, and soy which are most often the culprits. Keep away from poor quality ingredients such as ANY type of meat and bone meal, "meat", poultry, and other vague ingredient descriptions. What exactly is "meat" anyway??
Please contact your veterinarian with questions regarding this condition.
Show Sources & Contributors +
Dog Owners Home Veterinary Handbook
Publisher: Wiley Publishing, 2007
Authors: Debra M. Eldredge, Liisa D. Carlson, Delbert G. Carlson, James M. Giffen MD
The First Aid Companion for Dogs And Cats
Publisher: Rodale Inc, 2001
Authors: Amy D. Shojai, Shane Bateman DVM