It's usually pretty obvious when your pet rabbit has a head tilt but the reasons behind it are a little less straightforward. There can be a few reasons why your rabbit is suddenly cocking his head to one side or the other but regardless of the reason, your rabbit needs to see an exotics vet.
Encephalitozoon cuniculi, more often referred to as E. cuniculi, is a lifelong, debilitating disease that you don't want your rabbit to get.
It causes a myriad of symptoms but most often head tilt and seizures are seen in pet rabbits. What makes it difficult is that a perfectly healthy rabbit can suddenly come down with symptoms and there is no yes or no test that will tell you or your exotics vet 100% if your rabbit has the infection. The head tilt can become so profound that rabbits will roll and be unable to sit up. Their heads can almost be upside down because the head tilt has gotten so bad. They may have difficulty eating and some days it can be worse than others. Medications can help manage the disease but it is very contagious to other rabbits (and immune compromised humans) and no cures have been established for it. This is often a disease that is diagnosed after other diseases that cause a head tilt have been ruled out. Lifelong medicating and nursing care will be required to stabilize a rabbit with a severe infection of E.
Ear Infections in Rabbits
Your rabbit can get an ear infection in one or both ears. It can be a bacterial or yeast or mixture of both kinds of infections and definitely can cause a head tilt in rabbits. Your exotics vet will take a sample of the debris in your rabbit's ear (it may just look like wax), smear it on a glass slide, stain it, and look at it under a microscope to see if there is an infection.
Topical medications (ear drops) are usually prescribed to treat ear infections in rabbits. If the ear infection is really bad or has been left untreated for a long period of time the head tilt may remain even after the ear infection has resolved with medications. Some head tilts may remain permanently and rabbits will adapt with their new tilted view on life and do just fine.
Rabbits are very prone to abscesses (pockets of an infection that produce pus). They can get them just about anywhere it seems and if they are in the area of the ear canal they may cause a head tilt. Tooth abscesses, abscesses behind the eye, or abscesses under the skin by the ear may all put pressure on the ear canal causing your rabbit's equilibrium to be off and give them a head tilt. Depending on where the abscess originates it may require antibiotics or surgery to remove it.
If an abscess is due to a molar in your rabbit it will need to be extracted under anesthesia. The abscess may also be infused with antibiotics, surgically opened to allow it to drain, and cleaned out. Abscesses are not fun to deal with. They can be very difficult to get rid of and no one likes to give medications to their pets.
You may or may not see a bulge under your rabbit's skin indicating he has an abscess.
Ear mites are tiny little pests that make their homes in the ear canal of many kinds of animals. Rabbits are prone to these arachnids and when they are feeding on the ear wax in your rabbit's ear it can be very loud, painful, and annoying to your rabbit. These side effects of the ear mites may cause your rabbit to tilt their head, shake their head, scratch at their ear, and rub their head on the ground. Ear mites are usually pretty easy to get rid of but you need to make sure a medication that is safe for rabbits is used. If the wrong medication is used you could cause harm to your rabbit such as deafness, pain, and even death. Ear mites can easily be seen under a microscope by your exotics vet and typically once the infestation is cleared up the head tilt will go away.