Skin Abscesses

 

 

Esther van Praag Ph.D.

Warning: this page contains pictures that may be distressing for some persons.

An abscess is a pocket of fluid and pus, which results from an attack by pyogenic organism (e.g., bacterium) followed by the destruction of cells. The pocket usually contains a collection of pus, dead phagocytic white blood cells, necrotic cells, and live or dead bacteria. As the quantity of pus increases, the pocket grows larger and starts to wall off from the surrounding tissues and blood circulation. This renders treatment difficult. If the abscess is left untreated, it continues to grow. Tissue will rupture either inside the body or on the surface of the skin. This stage is particularly painful and dangerous, with the liberation of bacteria and their toxins in the blood circulation.

Caroline Charland

Rescued rabbit with a runny eye and a facial abscess that was left untreated. As a result, it burst and dried out. The presence of the abscess, the pain and poor health affected the quality of the fur, which look dull and unkept.

In most cases of abscess, the rabbit has a history of pasteurellosis, though other bacteria like Staphylococcus aureus, Streptococcus sp., Pseudomonas sp or Fusiformis sp. are no exceptions. They often result from a nasolacrimal or tooth problem, surgery, insect bites, scratches or skin wound, trauma, or a foreign body such as a hay splinter in the gum, foot sole or anal gland.

Abscesses are typically found on the head, neck and shoulders regions, but can also affect other parts of the body, organs or bones. During palpation, abscesses feel either as a hard lump or a soft doughy swelling that can be moved. The presence of an abscess is usually painless, unlike other animals. It is often observed that abscesses can grow within a few days time.

 

MediRabbit

Subcutaneous abscess on the ventral abdomen of a female rabbit

Clinical signs

There are no specific clinical signs, except the presence of a lump, an unusual swelling, reduced appetite, increased water intake, and/or fever.

 

Michel Gruaz

 

Tick paste-like pus emerging from the opened abscess cavity

Anonymous

 

Rabbit with abscesses on the cheek and above the eye. After carefully trimming the fur, the abscesses were opened, debrided and flushed with an antiseptic solution. The white deposit is dried pus.

Treatment

The treatment of an abscess is difficult, long, and recurrence is no exception in rabbits. Use of systemic antibiotics will have little effect and more aggressive therapy is needed.

The best option remains total surgical excision of the abscess cavity, necrotic tissue, and the surrounding fibrous capsule. This treatment can, however, not be done when several abscesses are present, or when the bone is affected (e.g., osteomyelitis, jaw bone infection by a tooth root). During the surgical procedure, it is important to check that no fibrous channels leading to abscess cavities deeper in the tissue remain. If present, the cavities must be flushed with antiseptic solutions (e.g., chlorhexiderm or iodine povidone) by means of a catheter tube. A drain can be placed to facilitate this procedure.

The cavity should be packed with an antibiotic impregnated dressing. Various types are available nowadays include:

Permanent placement of antibiotic impregnated PMMA beads;

Temporary filling with antibiotic impregnated gelatin or cellulose hemostat (e.g., GelFoam, Surgicel). The dressing must be changed daily or every 2nd day, to avoid necrosis of surrounding tissues;

Temporary filling with wet-to-dry hygroscopic and bactericidal sugar dressing (e.g., 50% dextrose, or manuka or clear sterilized (g-rayed) honey). The dressing must be changed daily, to avoid necrosis of surrounding tissues.

The later filling presents the advantage to remove the malodorous smell of ammonium and sulfur compounds due to bacterial breakdown of serum or cell proteins.

If osteomyelitis (bone infection) has developed, systemic administration of antibiotics is necessary. Antibiotics of choice include those that penetrate the bone or joints, e.g., chloramphenicol, fluoroquinolone (enrofloxacin or marbofloxacin), bicillin (a combination of penicillin G benzathine and penicillin G procaine), or penicillinase-resistant semi-synthetic penicillin such as cephalosporin or metronidazole. The choice of antibiotics safe for use in rabbit is limited.

 

Orlando Diaz

Abscess at the base of the ear

Orlando Diaz

Four weeks after the surgical debridement and an antibiotic (bicillin) treatment

Orlando Diaz

After opening the abscess capsule, debridement and marsupilisation to keep the wound open for easy treatment

 

The treatment needs to be aggressive and long (4 to 6 weeks). If this antibiotic treatment is not successful, or if large parts of the bone have been destructed, radical debridement remains necessary. Nowadays, gentamycin PMMA beads can be implanted near the bone.

There is little information is available about the effusion rate of the antibiotic from antibiotic impregnated gel sponge or beads. Newly grown tissue may hinder a good distribution of the antibiotics from beads after 3 weeks already, limiting their action to 6 weeks.

It should be kept in mind that abscesses in rabbits are difficult to treat and a full recovery without relapse cannot be guaranteed.

 

 

More detailed information on abscesses in rabbits and treatment options can be found in:

Skin Diseases of Rabbits

by E. van Praag, A. Maurer and T. Saarony,

MediRabbit.com, 2010.

Paperback, 408 pages.

 

Acknowledgement

Thanks are due (listed alphabetically) to Caroline Charland (www.bunnybunch.org, USA), to Dr. Orlando Diaz (Lake Howell Animal Clinic, Maitland-FL, USA), and to Michel Gruaz (Switzerland) for the gracious permission to use their pictures.

Further information

Aoyama T, Sunakawa K, Iwata S, Takeuchi Y, Fujii R. Efficacy of short-term treatment of pertussis with clarithromycin and azithromycin. J Pediatr. 1996; 129(5):761-4.

Blackwell NJ. Abscesses in rabbits. Vet Rec. 1999; 144(19):540.

Harcourt-Brown F. Rabbit Medicine and Surgery, Oxford, UK: Butterworth-Heinemann 2001, 192 pages.

Hillyer EV, Quesenberry QE. Ferrets, Rabbits, and Rodents: Clinical Medicine and Surgery New York: WB Saunders Co.,1997.

Ladefoged O. The absorption half-life, volume of distribution and elimination half-life of trimethoprim after peroral administration to febrile rabbits. Zentralbl Veterinarmed A. 1979; 26(7):580-6.

Ladefoged O. Pharmacokinetics of trimethoprim (TMP) in normal and febrile rabbits. Acta Pharmacol Toxicol (Copenh). 1977; 41(5):507-14.

Bergman A, Yanai J, Weiss J, Bell D, David MP. Acceleration of wound healing by topical application of honey. An animal model. Am J Surg. 1983; 145(3):374-6.

[No authors listed] Related Extraction and abscess treatment in a rabbit. J Vet Dent. 2000; 17(2):95.

Richardson V. Rabbits: Health, Husbandry and Disease. Blackwell Science Inc, 2000.

 

 

 

 

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