Abscesses in Rabbits

Abscesses in rabbits are a common and potentially serious problem. They are accumulations of pus that are formed by tissue degeneration and surrounded by a thick, scar tissue capsule. Abscesses form when bacteria or foreign bodies like splinters, lodge in tissue and cause a persistent infection. Abscesses are filled with a thick, creamy material called pus and can form in any tissue in the body.

The most common causes of abscesses in rabbits are bite wounds that become infected, tooth root infections, sinus infections and tear duct infections. Treatment of abscess in rabbits is different than treatment in dogs or cats, where antibiotics and simple lancing and draining of pus is often curative. Rabbits make a very thick pus that does not drain well, and the scar tissue capsule is usually very thick. Treatment of abscesses in rabbits almost always requires surgery.

What to Watch For

• Swelling
• Redness
• Signs of irritation or pain
• Excessive grooming
• Itchiness
• Discharge
• Moistened fur
• A firm, painful mass
• Drooling
• Persistent bad breath
• Facial swelling
• Depression
• Loss of appetite
• Weight loss

Diagnosis

Your veterinarian will not only have to diagnosis your rabbit's abscess – he will also have to determine what caused the abscess. Some tests that might be ordered are:

• History and physical examination, including a thorough oral examination (which sometimes requires sedation)
• Complete blood count
• Blood chemistry
• Cytology (microscopic evaluation of cells)
• Biopsy and microscopic evaluation of affected tissues
• Culture and antimicrobial sensitivity testing
• Radiographs (X-rays)
• Ultrasound

Treatment

Treatment of your rabbit will involve ridding the body of the abscess and making sure your pet remains healthy. This may include:

• Surgical removal of affected tissues
• Surgically opening and flushing the abscess, along with packing the abscess pocket with a material that has antibiotic properties
• Follow up treatment, consisting of re-packing or re-flushing the abscess pocket
• Antibiotics
• Fluids and supportive nutrition

Home Care

Proper care at home is critical, especially if your rabbit does not rapidly improve. Your veterinarian will give specific instructions for helping to care for your pet.

To prevent the abscess from returning, give all medications for the entire time period that they are prescribed, even if the abscess appears to have healed completely.

Keep infected rabbits in isolation during treatment. Monitor food intake and fecal output daily to assure proper food and water consumption and monitor weight daily.

Preventative Care

There are some important things you can do to help prevent your rabbit from forming an abscess. Keep sharp objects away from your rabbit and keep his living area clean and sanitized.

Avoid contact between rabbits and other animals that may result in puncture wounds from teeth or nails. To prevent life-threatening foot infections (pododermatitis), make sure your rabbit does not become obese. Use a soft bedding material and keep it dry.

Prevent your rabbit from chewing on sharp or fibrous objects that may cut the gums or inside of the mouth or that may splinter and cause penetrating wounds in the mouth.

If your companion rabbit is scratched or cut, see your veterinarian as soon as possible so the wound can be properly cleaned and treated.

Feed high quality grass or Timothy hay daily to keep the cheek teeth (molars) trim. Tooth root infections, caused by overgrown or uneven wear of cheek teeth, is the most common cause of facial abscesses.

See your veterinarian for treatment of watery eyes, sneezing or nasal discharge as soon as they are noticed. Untreated sinus, nasal or tear duct infections can result in abscesses.

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.

Diagnosis In-depth

Your veterinarian may use radiographs (X-rays) or changes in the types of blood cells (CBC) or enzymes found in the blood (blood chemistry) to evaluate the overall health status of a sick animal.

• Radiographs. The most common radiographic change associated with an abscess is a soft tissue mass in the affected tissue. Radiographs are used to determine if the abscess is invading an underlying bone (requires more aggressive and longer therapy), joint or internal organ. A full set of skull X-rays will determine which tooth roots are infected and need to be pulled. Radiographs may be helpful for determining if a foreign body is the cause of an abscess. Cysts, tumors, hematomas, fibrous scars and granulomas can appear radiographically similar to an abscess. Ultrasound may be used to determine if a mass is fluid-filled or solid and to determine if a foreign body is present in the mass. Some veterinarians may recommend a CT scan to determine the origin and extent of the abscess prior to surgical treatment. This is especially helpful in head abscesses, which may involve multiple teeth, sinuses or the base of the ear.
• Cytology. To confirm that the swelling is an abscess, and not a tumor, cyst or other type of swelling, your veterinarian may pierce it with a small hypodermic needle to collect cells. Sometimes, white pus will be visible within the syringe following this procedure, confirming the diagnosis. In most cases, microscopic examination of the cells is needed.
• If the abscess is completely walled-off and encapsulated, then there may be no changes in the white blood cell count. If the abscess has recently formed or is leaking infectious agents to the general circulation, then there may be a substantial increase in the number of white blood cells (neutrophilia) with or without toxic changes in these cells. In rabbits that are septic, the white blood cell may be decreased (neutropenia), with a high proportion of immature cells and/or toxic changes. This finding is associated with a poorer prognosis.
• Confirming the cause of an abscess is best achieved by obtaining a sample for culture and antimicrobial sensitivity to demonstrate the organism causing the infection. This test will identify the best antibiotic to use in continued treatment of the infection.

Therapy In-depth

• Complete surgical removal of an abscess is best if all of the affected tissue can be removed without causing problems in the rabbit. If complete removal is not possible, then as much affected tissue as possible will be surgically removed. Depending on the location of the abscess, your veterinarian may either pack the abscess or leave it open for flushing. In many cases, a substance that continuously elutes antibiotics will be placed within the empty abscess capsule. This could be gauze packing, a gel or bone cement beads which constantly give off antibiotic into the wound. Sometimes, medical honey is packed into the wound. If treated with gauze, the packing will need to be unpacked and re-packed until complete healing is achieved. With some skin abscesses, the wound can be left open to facilitate flushing and healing from the inside to the outside. or may not place a piece of tubing called a drain in your rabbit.
• Both local or topical and systemic (given by mouth or given by a shot), antimicrobial agents will probably be prescribed for your rabbit.. Long-term antimicrobial therapy may be necessary, particularly when bone is involved.
• Local abscesses will probably be treated on an outpatient basis. Rabbits with septicemia or with abscesses involving internal organs will probably be hospitalized for the initial treatment period.
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• Other therapies that may be needed include fluids to correct dehydration and supportive nutrition, if the rabbit is not eating or has lost considerable weight.
• Treatment is considered successful when a rabbit is removed from antibiotics and remains normal.

Follow-up Care

Optimal treatment for your companion rabbit requires a combination of home and professional veterinary care. Follow-up can be critical, especially if your rabbit does not rapidly improve.

• Make certain you administer all prescribed medications at the appropriate times. Finish the entire course of antibiotics, even if it looks as if the abscess has healed completely. Contact your veterinarian immediately if you have difficulty treating your rabbit as prescribed. If you are having problems, it may be best to hospitalized him to assure that a proper course of treatment is administered.
• Rabbits that are being treated for abscesses should be isolated from other animals to prevent transmission of infectious agents.
• For skin abscesses that are left as an open wound, make certain that the abscess stays open so it will heal from the inside to the outside. If a surgically opened abscess closes over, contact your veterinarian immediately.
• Once all packing has been removed, the swelling should resolve. If antibiotic beads are left inside the wound, you may be able to feel these. If you notice the swelling returning, see your veterinarian immediately.