Otitis externa and otitis media are two common ear problems in pooches. Here are the causes, symptoms and treatment for these ear problems.
Otitis externa is defined as an acute or chronic inflammation of the epithelium of the external ear canal which may also involve the pinna. The condition is characterised by erythema and increased discharges or desquamation of the epithelium with varying degrees of pain or pruritus. Contributing predisposing and primary factors for otitis externa must be evaluated or the condition is likely to become chronic, ultimately resulting in an end-stage ear with surgery the only viable option.
Otitis externa often results when a change in the normal environment of the ear canal causes the glands lining the canal to enlarge and produce excessive wax. Gradually, the outer skin (epidermis) and the inner skin (dermis) produce excessive fibrous tissue (fibrosis) and the canal becomes narrowed. It is normally a secondary symptom of another underlying disease, such as an infection.
While, otitis media is defined as inflammation of the middle ear and is an important perpetuating cause of otitis externa. Otitis media typically occurs as an extension of otitis externa, causing a ruptured membrane (tympanum) that separates the external ear and the middle ear.
Otitis externa and otitis media affect dogs and cats of any age and breed. As responsible pet parents, we can protect our canines from these ear problems.
Symptoms to look out for!
- Head shaking
- Scratching/itching at the external ear flaps
- Bad odour
- Redness and Swelling of the external ear canal
- Scaling skin or obstruction of the ear canal
- Tilting the head
- Un-coordination and
- Occasional vomiting
Causes of otitis
Foreign bodies: Plant material, dirt, sand, dried medicaments, cross-lodged hairs can cause otitis. Diagnosis is more complicated if bilateral or if the condition has progressed with the appearance of a purulent discharge which may be confused with a primary bacterial disorder.
Ear tumours and polyps: Patients with ear canal tumours or polyps will present with unilateral otitis externa and possibly otitis media. Common tumours include sebaceous gland adenomas and adenocarcinomas, ceruminous gland adenomas and adenocarcinomas, carcinomas of undetermined origin, and squamous cell carcinomas. All masses within the ear canal should be surgically removed as soon as possible and positively diagnosed by biopsy.
Bacterial: Cytology is very important to estimate numbers of organisms. More common pathogens include Staphylococcus intermedius, Pseudomonas aeruginosa, Enterococcus spp, and Proteus spp. ‘Swimmer’s Ear’ can be a problem in dogs resulting from a combination of water retention, epidermal maceration and secondary infection with Pseudomonas spp.
Mycotic infections: In otitis, fungal organisms isolated are candida spp and rarely dermatophytes.
Diagnosis of otitis
Techniques like otoscopy, pneumotoscopy, bulla radiographs, otic endoscopy and magnetic resonance imaging (MRI) may be used to identify the accumulation of fluid or soft tissue growth in the middle ear. Otitis media was diagnosed in over 80 percent of these ears with chronic otitis.
Vets also need to know the history of the pet and will conduct a complete physical examination as well as otic examination (pinna, otoscopic examination of the external ear canal). Gram negative bacteria is indicated by purulent, pale yellow, thick, tenacious, sweet smelling exudates while gram positive bacteria is indicated by light brown, creamy exudates. Ear mites symptoms include dark brown to black crumbly exudates while those for yeasts include dark brown sweet smelling exudates.
Vet will perform a cytological examination, bacterial culture and sensitivity and additional diagnostic, testing like skin scrapings, fungal cultures, thyroid evaluation, allergy testing (skin or serum testing for inhaled allergens), ear canal biopsy, CT scan and hemogram and serum biochemistry profile.
Treatment for otitis externa and otitis media usually involves outpatient care, unless the inflammation or infection has moved into the inner ear. In most cases of otitis externa, a topical therapy following a complete cleansing of the external ear is an effective resolution to the problem.
The topical therapy may consist of antibacterial, corticosteroid, anti-yeast, and antiseptic drops. In severe cases of otitis externa and otitis media – where the presence of infectious organisms has been confirmed – oral antibiotics and antifungal may be prescribed. Corticosteroids may also be used to reduce the animal’s pain and swelling.
Systemic antibiotics are prescribed for severe, chronic, or recurrent bacterial otitis externa and for all cases of otitis media. While, systemic antifungal agent Ketoconazole at 5-10 mg/kg/day should be considered along with topical therapy for treatment of yeast otitis media for 3-4 weeks, but should be continued until follow-up cytology confirms that the infection is cleared. Also, Zeps surgery can be performed for the correction of otitis media in dog.
Living and management
Follow-up treatments for otitis externa and otitis media involve repeat examinations of the ear discharge and control of any underlying diseases. With the proper therapy, most cases of otitis externa will resolve within three to four weeks, whereas otitis media takes a considerably longer time to treat it and up to six weeks to be resolved. If these conditions persist over long periods of time and are not treated, they may lead to deafness, facial nerve paralysis, otitis interna, and (rarely) meningo-encephalitis. So, take care of your pooch’s ears!
(Dr Vikash Sharma is MVSc & AH (surgery) at Animo Pet Care & Research Center, Patna.)