Chronic otitis is a long-term ear infection that can affect any dog and cause itchy, painful, and smelly ears. Here, our Moreno Valley vets discuss the causes, signs, and treatment of chronic otitis in a dog's ear.
Canine Chronic Otitis
Chronic otitis is a common disease of the dog's ear canal that can be externa (of the outer ear canal only), media (involving the middle ear), or internal (involving the inner ear and associated structures). It primarily affects the external ear canal and, to a lesser extent, the middle and inner ear, making it a dermatologic condition.
An ear infection is typically caused by irritation to the skin lining the ear canal, which causes inflammation and yeast and bacteria overgrowth. This causes itching and inflammation, which leads to self-trauma.
Any dog, regardless of ear shape, water exposure, or the amount of hair inside the ear canal, can develop an ear infection. In most cases, the underlying cause of the irritation is allergic or unrelated to conformation and moisture. Environmental and food allergies can also cause an allergic skin reaction leading to external otitis.
Other less common causes of otitis externa in dogs include:
- Polyps or other growths in the ear canal
- Foreign bodies in the ears, including dirt, sand, or plant material (foxtails and grass awns)
- External parasites (like ear mites)
Chronic otitis is a painful condition caused by inflammation, infection, and thickening of the ear canal's tissues. This causes ear canal narrowing, ruptured eardrums, and debris and infection within the middle ear. Scar tissue occludes the canals over time, preventing medications from reaching the diseased portions of the canal and preventing the natural sloughing of skin cells, sebum (wax), and hair from the canal.
Chronic otitis is a frustrating disease for both owners and veterinarians, but it is far more critical for patients due to the pain and nagging itchiness that these ear infections cause.
Signs of Chronic Otitis in Dogs
The clinical signs of otitis depend on the severity of the inflammation, but may include:
- Shaking the head or rubbing the head and ears on the floor or furniture
- Scratching at the ears
- Discharge from the ears, which can sometimes have a foul odor
- Redness of the ear canal and earflap (the ears may also feel warm when touched)
- Ear hematoma, evidenced by a grossly swollen earflap
- Aggression whenever the head is approached
Progression of this infection into the middle and inner ear can result in even more severe clinical symptoms, such as head tilt, incoordination, inability to stand or walk, hearing loss, and severe, unrelenting pain. If the otitis is severe or chronic, the outer ear canal can thicken and become deformed, making it difficult to clean the ears.
When attempting to diagnose an ear infection, a veterinarian can benefit from a medical history and physical examination findings. The medical history may include attempting to determine the duration of the ear infection, whether it has occurred previously, and whether any other signs of illness have been observed. The results of a physical examination may reveal evidence of an underlying illness, such as thyroid disease or Cushing's disease.
Chronic otitis is typically diagnosed based on a history of previous ear infections and physical examination findings. Redness, inflammation, discharge, and other changes within the ear will readily indicate the presence of an ear infection, but the difficult part will be determining what types of microorganisms are exploiting the dog's inflamed ears and what is causing the inflammation in the first place. In these cases, specialized diagnostic testing, like otic cytology, will likely be recommended.
Treating Chronic Otitis in Dogs
Chronic otitis treatment entails addressing the bacterial and fungal components, as well as the inflammation, with antibiotics.
The treatment steps are usually as follows:
- Cleaning the ear canal is always advised to remove accumulated debris. If the otitis is painful and/or a lengthy process, cleaning should ideally be done while the pet is sedated or anesthetized. Otoscopy is frequently recommended as a tool in this process.
- Typically, topical medication tailored to treat the specific bacteria, yeast, or mites present is used (these are usually available as ear drops or ointments). Antibiotics, antifungals (to kill yeast), anti-inflammatory drugs (such as cortisone), and topical anesthetics are examples of these.
- In some cases, such as when the eardrum is ruptured, systemic antimicrobials (antibiotics administered by mouth or injection) are indicated. Antibiotic therapy should ideally be based on the results of culture and sensitivity testing.
- To alleviate pain, redness, and swelling, systemic anti-inflammatory medications such as corticosteroids are sometimes used. Antihistamines may be prescribed as well.
To stop this disease, the underlying illness must be treated, which can range from mass removal and mite killers to diet changes and allergy injections. In difficult cases, surgical intervention may be required.