Pruritis is the sensation that makes an animal scratch, rub, chew, or lick a certain area of its skin. This is often an indication that the skin is inflamed, which can occur in any of the many dermal layers. In rabbits, most cases are linked to a parasitic challenge, so always be on the lookout for mites, fleas and ticks. If you find the animal becomes intensely itchy by rubbing the skin, it’s time to investigate.
Posted: 11 February 2019
A. Psoroptes cuniculi (the rabbit ear mite);
The most common parasite you’ll be looking for is Psoroptes cuniculi, the rabbit ear mite. This is a non-burrowing mite that feeds on blood and serum. Many thousands of ear mites can affect the external ear canal and pinna, creating hyperkeratosis and a thick, dry, red/brown crust. Intense erythema develops as a result of the inflammation caused by the mucus and faeces from the mite. This in turn causes pruritis and head shaking, which is both painful and debilitating. Look for some of the following;
Treatment involves the use of systemic anti-parasiticides.
Cheyletiella parasitovorax is a non-burrowing mite which causes a scaly dermatosis. It mainly affects rabbits, but it can also be found on cats and dogs (usually when they’re young, old or debilitated) and people (it’s zoonotic, producing papules, erythema and itching in areas of skin close to where the rabbit has been handled). Diagnosis is made by finding mites on skin scrapings or acetate tape preparations. It’s most likely to be found on the dorsum and neck of the rabbit, where it causes “creeping” dandruff, seborrhoea and pruritis. The mite can also cause a hypersensitivity reaction. Recommended treatments include Selamectin and Ivermectin, though always make sure you stick to the rules of The Cascade.
Rabbits will often pick up fleas from dogs and cats when they live in the same environment, but they also host their own flea, Spilopsyllus cuniculi. This flea is usually found in clusters around the bases of the rabbit’s ears (you can also find these on cats, with rows of fleas attached to the edges of the ear causing intense irritation), and plays an important role in the transmission of Myxomatosis. A recommended treatment for the rabbit flea is Imidacloprid, which is both safe and effective.
These are often found in small numbers in rabbits, so the occasional louse wouldn’t normally be considered a problem. However, when found in large numbers, this would indicate an infestation which may be associated with another skin parasite or an underlying systemic disease making the animal debilitated, run-down and malnourished. You’ll need to take multiple skin scrapings to make a diagnosis. Have you read our article on Skin Scrapings? Haemodipsus ventricosus is the rabbit biting louse. It’s quite large and can be seen with the naked eye. If found, it is often an indication of poor husbandry, especially in breeding colonies. Look for them around the head, ears, neck, shoulders and genitalia. These parasites will cause intense itchiness and relentless scratching and licking. They may develop a coarse, roughened coat with erythema, inflammation and secondary bacterial infections. Some rabbits will become lethargic and lose weight. Some patients may become so infested that they develop mild or severe anaemia.
E. Sarcoptes scabeii
Sarcoptic mange has been reported in pet rabbits, especially when kept together in large groups. It’s always wise to be aware of the possibility as they present a zoonotic danger. Look for wounds on the lips, nose, head, neck and genitalia. This parasite will cause intense pruritis, which will result in alopecia. Self-mutilation will lead to wounds and secondary bacterial infection. Diagnosis is made from skin scrapings and microscopy, as well as PCR.
F. Contact dermatitis
Many rabbits are housed and bedded with shavings and newspaper, and as a result, many develop contact reactions to the wood, pine and ink dyes. Other contact irritants include disinfectants and cleaners which are used to clean the housing. Affected rabbits will have lesions on their hocks, feet and abdomens where they come into contact with the floor and bedding. They can also develop erythema and inflammation on the ears and face, where the chemicals can be spread through grooming. Diagnosis is helped by taking a detailed history of when the problem started and relating it to any changes in care and husbandry.
Choosing the most effective drug for parasitic infestation in rabbits will depend on numerous factors, including cost, number of animals affected, ease of administration and the cascade. Some of the more common treatments include Ivermectin, Selamectin, Imidacloprid, Lufenron and Moxidectin. Before using any of these products, make sure you follow the rules of the cascade.
Remember to prescribe under the rules of the Cascade.
Some of these treatments are not authorised by the Veterinary Medicines Directorate (VMD) for use in rabbits. You must explain the ‘prescribing cascade’ in further detail to your client and also explain why the drug is prescribed. Owners should sign a consent form stating that they understand the reasons that the drug is being prescribed and its possible complications, before the treatment is issued.
Do NOT use Fipronil in rabbits
This drug has been associated with fatalities. The mechanism of toxicity in rabbits is unknown, but we do know that its oral absorption can be extremely high, as much as 50%, and if applied in a place that can be licked, will certainly result in a problem.