Rabbits shouldn't itch themselves any more than you would. If your pet rabbit seems excessively itchy or scratches a lot then they may have a problem that needs to be addressed. Various things can cause a rabbit to itch or scratch but thankfully this pruritis is treatable.
Rabbit Fur Mites
Cheyletiella parasitivorax are microscopic mites that live in the fur of rabbits. These little mites may start off in a small area on your rabbit but if left untreated they can spread all over your rabbit's fur, into the environment in which they live, and even to other rabbits and pets.
Cheyletiella are blood sucking parasites that have to bite your rabbit in order to feed. This biting is what is causing your rabbit to itch or scratch.
Fur mites are highly contagious to other rabbits. If you have other pets in your house and your rabbit is diagnosed with Cheyletiella care should be taken to not spread these parasites to other animals. Wash your hands after handling your rabbit, throw away the food and bedding in their cage, and freeze all unused food and bedding that you purchased from a pet store or online. Mites can be brought in to your home from items such as these so freezing them before use is also a good way to prevent an infestation. Even if your rabbit never goes outside they can get fur mites.
Fur mites are also referred to as "walking dandruff" because they are often seen moving dead skin around on your rabbit creating the appearance of mobile skin cells. If your exotics vet diagnoses your rabbit with these mites they will most likely prescribe a medication to kill the mites that won't harm your rabbit, such as Selamectin.
Over the counter products are not typically safe for rabbits and you should always consult your veterinarian prior to administering any product to your rabbit.
While not as common as some other parasites, lice do infest rabbits. Lice are species specific so humans and other pets that aren't rabbits cannot get them.
Treatment is similar to that of fur mites.
Fleas on Rabbits
Many people don't think that rabbits can get fleas but the reality is that any pet with fur can, including our pet bunnies. Fleas, like fur mites, are blood sucking parasites that bite rabbits which in turn causes them to itch or scratch. Fleas lay about 40 eggs every day so even if you only see one or two adult fleas on your rabbit they've probably already laid hundreds of eggs. Fleas can also bite humans but we are not viable hosts to these pests so they cannot survive solely off of our blood.
Indoor rabbits can get fleas just like outdoor rabbits. Other pets in the household can give your rabbit fleas and we can track fleas in from the outdoors. Fleas can also find their own way into our homes just like other insects, such as ants and spiders.
Using a flea comb you can find fleas and flea dirt (their cylindrical feces that will turn red if rubbed into a wet cotton swab to identify that it is digested blood and not just environmental dirt). If you find either of these on your rabbit then you need to treat your rabbit and all other pets with fur in the household with a safe medication, just like you would do for fur mites.
You will also need to treat the environment, clean, and freeze all food and bedding items that you can. Some rabbit owners will also use boric acid powder in their carpeting and various sprays and room bombs sold at pet stores. If you choose to use these products make sure your rabbit is out of the room you are treating for at least 24 hours.
Dry Skin on Rabbits
Your rabbit can develop dry skin and itch or scratch. Rooms with very low humidity, dusty environments, poor diets, and bathing your rabbit too often with inappropriate shampoos can all contribute or cause your rabbit to have dry skin. If you can determine the cause for the dry skin then you should be able to reverse it. If you need temporary relief for your rabbit's dry skin there are rabbit-safe spray products available.
Rabbit Ear Mites
Psoroptes cuniculiis are ear mites of the rabbit and cause itching and scratching.
Ear mites can be spread from rabbit to rabbit so wash your hands after handling a rabbit with itchy ears. You may notice hair loss around the ears, scabs, or especially dirty looking ears in rabbits with ear mites. These are all signs that your rabbit may have ear mites and needs to see their veterinarian. A head tilt, flopped ear, or head shaking are also signs of an ear mite infestation since both ears are not always affected.
Ear mites can easily be diagnosed and treated and prevention can be done the same way you would prevent your rabbit from getting fur mites and fleas - by freezing food and bedding that was purchased from the pet store prior to use.
Allergies in Rabbits
Just like some people, rabbits can be sensitive to certain things and even have allergies that can cause them to itch or scratch. Usually these allergies are environmental and not food based so changes can be made with bedding, cleaners, and air purifiers to make your rabbit more comfortable at home. Rabbits can also be allergic to parasites, such as fur mites and fleas, which will make an infestation of these pests even more irritating to your pet. Common environmental allergens to rabbits are laundry softeners and detergents with rabbits who have blankets. Using softeners and detergents meant for babies or sensitive skin (fragrance free varieties) are often best to use with rabbits who have allergies.
Skin Irritants to Rabbits
In addition to allergies, rabbits can also be irritated by certain items, especially if they aren't meant for rabbits. Shampoos, conditioners, sprays, air fresheners, etc. can all be irritants to rabbits. If you use a new product, such as a shampoo, and the next day your rabbit is itching, it may be because the shampoo was too harsh for your rabbit's skin. This is often seen with products meant for dogs that are used on rabbits.
Ringworm in Rabbits
Caused by two main types of fungus (Trichophyton mentagrophytes and Microsporum canis), ringworm is a fungal infection that causes hair loss, itching, and red "ringworm" lesions in rabbits.
It is usually treated with topical ointments or oral medication prescribed by your exotics vet. Rabbits contract ringworm from a variety of ways including contact with another infected rabbit, brushes that were used on a rabbit with ringworm, and dirty environments. People can also contract ringworm from a rabbit.
The main cause of ringworm (as well as mites and fleas) is direct contact with another rabbit so if you decide to welcome a new rabbit into your home be sure to keep them separate from your other rabbits until you are sure they do not have an infection.
Skin Infections in Rabbits
A rabbit with urine scald, feces that has remained in prolonged contact with your rabbit's skin, and overall unclean environments may cause your rabbit to develop a skin infection. These infections can be itchy to your rabbit and typically need prescription medications to remedy them. Anti-itch spray are available that are safe to use on rabbits but if they root of the problem is not addressed they are merely providing temporary relief.