Otitis Externa and Otitis Media in Rabbits
Inflammation of the external ear canal in rabbits is the term used to describe a group of symptoms or clinical signs that appear together, generally redness and swelling of the outer ear tissue. Clinically, this condition is known as otitis externa (otitis – inflammation of the ear; externa – external).
Otitis media – inflammation of the middle ear – often occurs as an extension of otitis externa. A middle ear infection is more likely to occur if the outer ear infection leads to a ruptured tympanum, the middle part of the ear canal where the ear drum is found. Otitis externa, meanwhile, typically coincides with other adjacent diseases or infections, like an upper respiratory infection or the common cold.
Symptoms and Types
The signs and symptoms of otitis media and otitis externa vary. They may include:
- Redness and swelling of the external ear canal
- Thick, white and often creamy exudate (fluid) at the ear canal
- Abundant ear wax or excessive ear wax
- Odor in and around the ear (not common with otitis externa)
- Crusts around the ear canal
- Shaking of the head
- Digging at the floor or holding the ear down as if in pain
- Inability or disinterest in eating
- Patchy hair or hair loss around the ears
- Scaling around the ear canal, which can lead to obstruction and hearing problems
Otitis externa typically occurs when another infection, like an upper respiratory infection or head cold exists. Rhinitis, sinusitis, or other infections in the proximity of the ear canals can increase the risk of ear infection, as can bacterial infections including Staphylococcus aureus, and yeast infections. Parasites, such as ear mites, are also a common cause for otitis externa. Sensitivities, or allergies, are another finding in some cases. Rabbits are well known for their hypersensitivity to ear cleaning solutions, for example. Your rabbit may have had a reaction to the cleaning solution itself, or to an overly vigorous cleaning.
To diagnose otitis externa and media your veterinarian will want to diagnose the underlying condition that is contributing to the problems and symptoms causing the condition. For example, bacteria often contributes to problems of the ear, including the accumulation of excessive ear wax.
The diagnosis will include identification of the scaling and crust around the ears that may be contributing to the obstruction. Your doctor will take a sample of the crusted tissue on the ear for laboratory analysis, the results of which may show the presence of bacterial infection in the ear, or parasites. It is also possible that neither of these findings will be present, if the condition is being caused by a sensitivity to over washing or to a product being used on the rabbit's skin.
Otitis externa and media may also be diagnosed through a head tilt examination, where the veterinarian will notice that the rabbit is holding its ear down in an attempt to control the pain. This reaction to ear pain is not the same as a head tilt.
A true diagnosis of head tilt is when a veterinarian has found lesions to the vestibular system -- the sensory system that gathers information about body movement so that the body can remain upright and balanced. Problems with the physical structure of the head are evident in rabbits with a formal head tilt.