Abscesses in Rabbits
Dr. Branson Ritchie
Abscesses form when invading infectious agents lodge in tissue and cause a persistent infection. As part of the body's defense mechanism, the immune system stimulates the production of cells and secretions that attempt to wall off and destroy invading organisms or foreign bodies; a wall of fibrin (scar tissue) creates a thick capsule surrounding the abscess.
Abscesses are typically filled with a creamy material that is usually white, yellow or grey, in color. This creamy material is pus and is formed by the body's attempt to liquefy and remove dead or dying cells. The consistency of pus that rabbits create is very thick, and will not drain with simple lancing.
Cysts, tumors, hematomas (swelling of blood), fibrous scars and granulomas (granular formation of cells), can cause swellings that appear similar to an abscess. Bot fly larvae may cause swollen areas in the skin of rabbits housed outdoors. All of these can be mistaken for abscesses. Your veterinarian will perform diagnostic tests to determine what is causing the swelling.
In rabbits, the most common cause of abscesses arising from the tear ducts or sinuses is Pasturella multocida.. Abscesses associated with the hock are usually contaminated with staphylococcus. Abscess of the jaw or face are nearly always caused by tooth root infection, and anaerobic bacteria are the cause. Any foreign material, such as splinters or hay can cause an abscess.
Abscesses can form in any tissue in the body like the skin, muscle, walls of blood vessels, liver, lung, heart and brain. The clinical changes that might occur vary with the location of the abscess. Abscesses in the skin can migrate internally, which may lead to septicemia (infection in the blood) and death, or may migrate externally allowing the pus to be released from the body. Infections that originate in the middle or internal ear, tooth roots, lungs or nasal sinuses may spread to and cause abscess formation in the brain, which are particularly dangerous.
Abscesses involving the skin, tissue around the eyes or lining of the mouth are recognized by swelling, redness, heat or signs of focal irritation or pain. A deeper abscess should be considered in rabbits that excessively groom or constantly scratch at the same area. The sudden moistening of fur with a thick creamy discharge that is usually malodorous, might indicate that a deep abscess has recently ruptured. If this clinical change is noted, seek veterinary attention as soon as possible so that any deep tissue damage can be treated and any infectious material that may still be present in the deeper tissues can be removed.
Abscesses in the lining of the mouth or associated with the teeth may cause excessive salivation and persistent malodorous breath. Abscesses in the back of the mouth may be associated with difficulty swallowing or difficulty breathing.
Abscesses can be life threatening if not treated appropriately and in a timely manner. If the body is not successful in walling off an infectious agent, then the site of a persistent infection can be a center for producing millions of infectious organisms (or large quantities of toxins from the infectious organism), that can enter the blood stream and seed infections in other organs or cause system failure and death. Seek veterinary care immediately if a mass is noted, the mass suddenly disappears, and the rabbit becomes acutely depressed or lethargic. These changes could indicate that an abscess has ruptured with the toxic material contained in its center is being released to the blood stream.
In well-walled off abscesses, the rabbit may appear to be clinically normal with no recognizable changes in attitude or appetite. Even if the abscess is very large, and destroying bone and other surrounding tissues, many rabbits do not act painful. Therefore, it is very important to you notice the swelling, because without treatment, these abscesses can be fatal.