Ears
Ear disease in rabbits is unfortunately a very common problem. Ear infections (the most common form of ear disease seen in rabbits) are classified by which part of the ear is affected. Those affecting the external ear are known as otitis externa and middle and internal ear infections are called otitis media and otitis interna respectively. The rabbits that are most vulnerable to these infections are the rabbits that have anatomically small or closed-off ear canals, which are the lop-eared breeds. These rabbits have been selected for their endearing droopy ears but have unfortunately developed very narrow and occasional completely closed ear canals. This means everyday cleaning of their ears is difficult, and bacteria and wax often build up in this dark, warm environment. There are certain breeds of rabbits that are more resistant to ear infections, such as Netherland dwarfs and large breeds with upright ears.
A standard part of every rabbit’s annual check up consult should be an ear exam. It is not uncommon for rabbits to hide their ear infections for weeks or even months, so having regular ear checks can help pick up any underlying disease your rabbit may be hiding.
Rabbits can show a variety of clinical signs with ear disease, but many will show no signs at all. Depending on what part of the ear is affected, rabbits may show different signs:
Scratching at their ears more frequently
Scratching their face, below their ear. You may be able to feel scabs there due to repeated scratching
Appearing quieter or less interested in food
Repeated episodes of gastrointestinal stasis
Head tilts or facial asymmetry - dropping of one side of their face
Otitis Media and Interna in Rabbits
Otitis media and otitis interna are conditions in which there is inflammation of the middle and inner ear canals (respectively) in rabbits. It is most commonly caused by a bacterial infection that has spread from the external ear cavity into the inner ear. In the initial stages, the rabbit may feel nausea related to the ear infection and may demonstrate loss of appetite with refusal of food. It may also affect the rabbit's nose and the throat if the infection spreads.
The ears, the vestibular system (inner ear balance mechanism), the nerves in the ear area, and the eyes may all be affected. This is one of the most common disorders seen in pet rabbits overall, but lop-eared rabbits are more likely to show signs of otitis externa (inflammation of the outer ear).
Symptoms and Types
Symptoms are related to the severity and extent of the infection; they may range from none to mild discomfort to signs of nervous system involvement. Other common signs associated with otitis media and interna include:
Sudden loss of balance, dizziness
Head tilting to one side
Lean or roll toward the affected side (this may appear similar to a seizure)
Anorexia or teeth grinding due to nausea
Reluctance to move, digging at the cage floor
Pain – reluctance to chew, shaking the head, pawing at the affected ear, holding the affected ear down
Facial nerve damage - facial asymmetry, inability to blink, discharge from eye, ipsilateral head tilt (tilting head on affected side)
Discharge from ears, dry eyes, throat infection
Causes
If only one side is affected, it may be due to foreign bodies, trauma, and tumour. However, bacterial infection is the most common cause of otitis media and interna. Other underlying causes include:
Candida, a fungal yeast
Ear mite infestation
Vigorous ear flushing can leave tissue irritated and susceptible to infection
Impaired immune system (due to stress, corticosteroid use, concurrent disease, debility) also increases susceptibility to bacterial infections
Ear cleaning solutions may be irritating to the middle and inner ear (avoid using any internal medications of fluids if the eardrum is ruptured)
Diagnosis
There are several causes for ear infection, and your veterinarian will need to distinguish from other causes of head tilt and rolling episodes. You will need to provide a thorough history of your rabbit's health leading up to the onset of symptoms.
Some of the following may be done -
*A complete blood profile will be conducted- including a chemical blood profile, a complete blood count, and a urinalysis.
* Your vet may take a tissue sample.
The results of these tests may show an underlying bacterial infection that has migrated to the ear, a fungal yeast infection, or the presence of parasites.
* Visual diagnostics may include X-rays of the ear and face region to look for evidence of foreign materials that have gotten lodged in the ear canal, or tumours that are blocking the canal.
*A computed tomography (CT) can be used for better resolution and visualisation if the X-ray does not give your doctor enough information. This option will only be available in limited/highly specialised clinics.
Treatment
Fortunately, ear infections can be managed in several ways. Depending on the type of ear disease your rabbit has, your veterinarian may offer you one or more of the following:
Daily ear cleaners– this option is for very mild ear disease where wax may be building up in your rabbit’s ears.
Antibiotic ear flushes– this is often the first treatment offered when your rabbit is diagnosed with an external ear infection.
Long term antibiotics– this is an option for persistent ear infections where further tests or treatment is not a viable option for your rabbit.
Surgical ear flushing– if the infection of your rabbit’s ear is severe but limited to their external ear, a veterinarian may offer to clean your rabbit’s ear under a general anaesthetic. At the Unusual Pet Vets, this technique is combined with an endoscope to look deep inside their ears to treat more stubborn infections.
Advanced imaging and surgery– many rabbits have underlying middle ear disease that spreads to the external ear. In these cases, treating the external ear infection alone is often unsuccessful, so surgery of the middle ear is performed. Middle ear disease can only be confirmed on advanced imaging such as CT which is only available at specialised clinics.
There is no one treatment that will be successful for every rabbit with ear disease, and some rabbits will have more than one option that is offered for them.
If the infection is severe, inpatient treatment may be advised, or when neurological signs are seen. Fluid and electrolyte therapy will be given until the rabbit stabilises, with bacteria specific antibiotics administered orally, and also applied directly in the ears if the eardrum has not ruptured. Antifungal medications will be administered of the infection is found to be caused by yeast. If the ear canal or eardrum has been severely damaged, it is possible that surgery will need to be performed to remove the ear canal.
Your rabbit will be discharged from inpatient care once it is stable, or if the infection was not severe, your doctor will prescribe the appropriate medications for you to administer at home. Generally, a warm saline solution can be used to clean and disinfect the ears, followed by gentle drying with a swab. Unless your veterinarian has instructed you otherwise, you should not put any solution or material inside the rabbit's ears.
Source: Inflammation of the Middle and Inner Ear in Rabbits - PetMD
Further Reading:
Middle and inner ear (otitis media and interna) - MediRabbit
Rabbits are a very popular pet seen at The Unusual Pet Vets, for a variety of reasons. Some come in for their routine vaccinations or a check-up, where others can be seen for serious conditions such as hindlimb paralysis or head tilts. A number of rabbits, particularly those with lop-ears, also come in for ear disease.
Rabbit Ear Diseases - The Unusual Pet Vets
Lop-eared rabbits have become very popular pets over the past few decades. These rabbits are born with ears that ‘flop’ over as they grow, as well as other characteristics such as shorter, more rounded faces. These attributes were used over time by breeders to give rabbits a ‘cuter’ appearance, but this has unfortunately led to ear disease becoming common amongst lop-eared rabbits.
Lop Eared Rabbit and Ear Disease - The Unusual Pet Vets
Ear Mites in Rabbits
Ear mite infestation in rabbits is caused by the parasite Psoroptes cuniculiis. They may be found in only one ear, or in both, and in some cases may spread to the surrounding areas – the head, neck, abdomen, and genital regions. The main symptom is skin scales on the inner ear, which turn into larger, thicker crusted lesions with surrounding hair loss. If left untreated, the lesions can become infected, putting the inner ear at risk of infection and subsequent hearing loss.
No specific breed or age is at higher risk, but the risk of acquiring ear mites can be increased with exposure to affected rabbits, such as in pet stores, shelters, or multi-rabbit households. The risk of infection can also be increased by exposure to mite eggs that have been lain in grass, straw, or wood chip bedding material.
Symptoms
Mild to moderate itching around the ear, head, and neck
Intense itching (more common) primarily located around the ears, head, and neck; occasionally generalised
Head shaking and scratching
Affected areas may become extremely painful
Thick, brown to beige crusty exudate in the ear canal
Occasionally, brown to beige crusting and itching occur on the ears and feet only
Hair loss and peeling of skin around the ears
Signs of ear infection may also occur
Mites and lesions may extend to the face, neck, abdomen, perineal region, and even feet via grooming
Diagnosis
Your veterinarian will first want to differentiate between other forms of infections and causes of scratching, but if mites are present, they will clearly be distinguished by your veterinarian. They may or may nor be visible to the naked eye, but the symptoms of Psoroptes cuniculiis infection are generally distinguishable as such. Your doctor will perform an examination of the ear, both by visual inspection and with specialised tools. An examination of exudates, the fluid that exudes/oozes from injured tissue, will be taken by ear swab and analysed by microscope. The blood and urine may be also analysed, usually with normal results.
Treatment and Care
The Psoroptes cuniculiis parasite is contagious, making it necessary to treat all rabbits that are in contact with the rabbit that is infected, and thoroughly clean and treat the environment in which the rabbit lives. Remove and discard all organic material from the cage, including wood or paper products, and bedding, replacing the bedding with shredded paper bedding that can be discarded. The cage should be thoroughly cleaned every day during the treatment period, with nothing reused. Combs, brushes, and grooming utensils will also need to be discarded, or thoroughly disinfected before reuse, otherwise, you will find that your rabbit has become reinfected.
There are specific drugs - namely Revolution and Ivermectin, that can be used to eliminate the mites from your rabbit's ears. The crusts on the skin should not be removed, as they will only reveal exposed tissue. Once treatment has begun and the mites are no longer infesting the crusted skin, the underlying skin will be able to heal and the crusts will fall away. Other ointments and preparations that may be used for the ear may include antibiotics for any infections that are found on the outer part of the ear. Oral antibiotics will be prescribed for inner infections. If your rabbit is in pain, your veterinarian will also prescribe a mild pain reliever.
Living and Management
An ear swab and physical examination should be done one month after the initial therapy has commenced. For most patients, the prognosis is excellent. In cases where the infestation is severe, and the ear drum has ruptured due to infection, a resulting inner ear infection can lead to permanent loss of hearing. This outcome is relatively uncommon.
In either case, continue to disinfect and maintain a very clean environment for your rabbit, and contact your veterinarian if it appears that there is a return of the parasites, or if your rabbit does not appear to have fully recovered.
Source: Infestation of Mites in the Ear in Rabbits - PetMD
More information about Mites can be found in the ‘Mites / Fleas / Lice / Fur Loss / Skin Issues’ file