An abscess is a cavity containing pus surrounded by a capsule of thickened, inflamed tissue. Usually an abscess is the result of a bacterial infection. The pus is an accumulation of dead cells from the battle to fight the infection. In humans, skin abscesses are often caused by Staphylococcus infections, but in rabbits, they can be caused by aerobic bacteria (those that require oxygen to survive) including Pasteurella multocida, Streptococcus, Pseudomonas andStaphylococcus, and a host of anaerobic bacteria (those that do not require oxygen to survive).
Rabbits can form abscesses in nearly any organ of the body as well as in skin, tooth roots and bone. The most common causes of rabbit abscesses are infections in tooth roots, tear ducts and bite wounds. Most facial abscesses are the result of dental disease. Tear duct abscesses can be the result of an elongated upper incisor tooth root blocking the tear duct. The accumulated fluid in the tear duct is a perfect breeding ground for bacteria and an abscess can form easily. Abscesses that form internally can be more difficult to diagnose or manage and include areas such as the uterus, lungs, heart, liver, abdominal fat, intestine and kidneys.
Rabbit abscesses can be challenging to treat. One problem is that the pus found in rabbit abscesses is thick, about the consistency of toothpaste, and does not drain easily when the abscess is opened. The reason for the thick consistency is that there is an enzyme missing that is in other mammals, such as dogs, cats and humans that can break the dead cells into a more liquid form. In addition, rabbit abscesses often develop finger-like projections or tracts into the surrounding tissue where new abscesses can form. If these tracts are not removed or thoroughly cleaned, the abscess will return.
There are many thoughts on how to treat rabbit abscesses and much depends on the location of the infection, the cause of the infection and the general condition of the bunny. It should be stressed, however, that no matter what treatment is chosen, it is vital to provide your pet with a healthy diet, daily exercise and a clean environment to enable the immune system to function at full capacity. It will often be necessary to perform diagnostic tests to investigate the cause of the abscess and to determine if other disease is present. These tests might include bacterial culture of the wall of the abscess (culturing the pus itself is not useful), x-rays and/or ultrasound to determine the location and extent of the infection, and blood tests to determine the response of the immune system and the condition of other organs.
No matter what treatment is selected, rabbit abscesses have a higher probability of returning than abscesses in cats, dogs or humans. This can be related to factors such as difficulty in removing all the abscessed tissue due to location, the inability of antibiotics in the blood to penetrate the abscess wall, draining tracts coming off the abscess, and the possibility that the underlying cause was not treated. Most experienced rabbit veterinarians feel that complete surgical removal of the abscess, along with treatment of the underlying cause, gives the rabbit the best chance for a complete cure. Ideally, all of the wall of all abscesses should be cultured for both aerobic and anaerobic bacteria to determine the best choice for antibiotic therapy with or without surgery.
It is not always possible to surgically remove an abscess due to its location, other disease (making anesthesia or a lengthy surgery dangerous) or financial restraints. In these cases the abscess can be opened, cleaned out thoroughly and flushed with an antiseptic solution. This procedure is usually performed under anesthesia, unless the abscess is very small. The wall of the abscess should be cultured for bacteria and an appropriate antibiotic can be selected. These wounds must be left open to be flushed at least twice a day for several weeks. If the abscess closes too quickly, it will merely fill with pus again.
Abscesses treated in this manner have a high rate of reoccurrence, but it may be possible to provide at least some measure of relief for your pet for a period of time. Please note that using antibiotics as the sole treatment without at least opening and cleaning the abscess is usually unsuccessful because these drugs cannot adequately penetrate the thick capsule of the abscess and kill the bacteria inside.
Other methods that have been used include injecting the wall of the abscess with effective antibiotics or other solutions at periodic intervals; packing the cleaned abscess cavity with gauze sponges impregnated with various products such as medical grade honey, 50% dextrose solution, antibiotics and enzyme products.
Most rabbit abscess cases will require the use of oral or injectable antibiotics. If the entire abscess is completely removed, then the antibiotics might not be necessary or may be used for only a short time. If the abscess was only lanced and drained, then antibiotic therapy might continue for weeks to months.
Some rabbits can live with abscesses on various parts of their body for years by having them surgically drained as needed. Rabbit abscesses form a thick capsule around the infection that effectively walls it off from the rest of the body. If the abscess is not causing pain, the rabbit may act as if nothing is wrong. However, this does not mean that if you see a lump on your rabbit’s body that you should ignore it. Your veterinarian should investigate any unusual lumps or masses as soon as possible. The sooner an abscess can be treated, the greater are the chances of a cure. In addition, some lumps are not abscesses at all but rather tumors or cysts and may need immediate removal.
The important points about abscesses in rabbits are:
- Feed your rabbit a healthy diet, provide ample exercise and a clean, safe environment to minimize the formation of abscesses. (See Rabbit Care for more information on general rabbit care.)
- Have all lumps investigated as soon as possible by your veterinarian.
- It is important to determine the cause of an abscess, not to just treat the abscess itself.
- There are several different ways of treating abscesses in rabbits based on location, cause, size, overall health of the bunny and so on. Consult with a rabbit knowledgeable veterinarian who will be familiar with the various options.
- If the cause of an abscess cannot be treated, there is a moderate to high probability it will return after treatment.
- Complete surgical removal of the abscess along with correction of the cause gives the best chance for a complete cure.
- Whatever the treatment choice, it is imperative to follow through with your veterinarian’s requested recheck appointments and diagnostic testing to improve the chances for abscess resolution.
by Susan Brown, DVM
Date Published: 3/6/2001
Date Reviewed/Revised: 01/05/2012
This is part of Dr. Brown’s Small Mammal Health Series.
Copyright 2012 – 2012 by Susan Brown, DVM. Used with permission. All rights reserved
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