Contributors: Rosanna Marsella, David Scarff

 Species: Feline   |   Classification: Diseases

Introduction Pathogenesis Diagnosis Treatment Outcomes Further Reading


  • Most common feline bacterial skin infection.
  • Cause: common sequela to a bite or scratch.
  • Signs: subcutaneous swelling, discharging pus.
  • Diagnosis: history, clinical signs.
  • Treatment: responds to drainage and antibiotic therapy.
  • Prognosis: generally good.
    Print off the Owner factsheet on abscesses Cat bite abscesses (and castration All about neutering) to give to your client.

Presenting Signs

  • Subcutaneous swelling.
  • Drainage of pus from skin Cat bite abscess .
  • Pain.
  • Anorexia.
  • Pyrexia.
  • Lameness in affected limb.
  • Lethargy and depression.



  • Organisms normally found within cats' mouths are also found within abscesses.
  • Pasteurella multocida Pasteurella multocidaBacteroides spp Bacteroides fragilis, beta-hemolytic streptococci, and fusiform bacilli.
  • For non-healing wounds consider atypical mycobacteria.

Predisposing Factors


  • An intact male cat with access to the outside environment will fight for sexual favors.
  • Cats in a population dense area will fight to maintain territory.
  • Immunosuppressed individuals, eg with feline leukemia virus Feline leukemia virus or feline immunodeficiency virus  Feline immunodeficiency virus, may show more severe signs, or fail to respond to appropriate therapy.


  • Cat bites and scratches are major cause   →   subcutaneous bacterial infection.
  • Bacteria are injected under the skin.
  • The small puncture wound heals rapidly.
  • Over the next 2-4 days bacteria multiply.
  • Normal defense mechanisms may fully clear the infection.
  • The infection may be walled off by fibrous tissue and rupture to the surface exuding cream   →   green pus with fetid odor.
  • Infection may spread locally or hematogenously, leading to cellulitis, local lymphadenopathy or other organ involvement.


  • 2-4 days.


Presenting Problems

  • Subcutaneous swelling.
  • Fever.
  • Lameness.
  • Pain.

Client History

  • Owner reports cat fight within previous 2-4 days.
  • Swelling typically on head, shoulder, tail base or hindlimb.
  • Off food.
  • Recently moved to new area   →   territorial disputes.

Clinical Signs

  • Cream to green foul-smelling purulent exudate from a skin wound Cat bite abscess .
  • Subcutaneous swelling, often painful, situated typically on the head or neck, tail base or a distal limb.
  • Regional lymphadenopathy.
  • May be few systemic signs.
  • May be fever, anorexia, depression and malaise.
  • Lameness.
  • Pain over affected site, often severe.
  • Cellulitis.

Diagnostic Investigation



  • May be considered in non-responsive cases.
  • Aerobic and anaerobic culture necessary Bacteriology. Include culture for mycobacteria. Negative anaerobic culture does not rule out anaerobic infection.

Differential Diagnosis


Standard Treatment

  • If already ruptured, clip and clean abscess with saline, dilute chlorhexidine Chlorhexidine or dilute hydrogen peroxide Benzoyl peroxide.
  • Liberal surgical drainage in non-ruptured abscesses will require general anesthesia General anesthesia: overview or heavy sedation Sedation or sedative protocol.
  • Cases which require extensive incisions will merit bandaging. If this is not possible place drain or leave open wound, eg side of face.
  • Oral antibiotics for 5-7 days. Choose bactericidal (clindamycin Clindamycin licensed for this use, but bacteriostatic) antibiotics with activity against the more frequently encountered organisms. Therapeutics: antimicrobial drug 
  • Non-steroidal anti-inflammatories in cases with pyrexia and pain Analgesia: NSAID.

Subsequent Management


  • May get overlying skin necrosis necessitating debridement.



  • Good in cats with healthy immune systems.

Expected Response to Treatment

Reasons for Treatment Failure

Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Hoshuyama S, Kanoe M, Amimoto A (1996) Isolation of obligate and facultative anaerobic bacteria from feline subcutaneous abscesses. J Vet Med Sci 58 (3), 273-274 PubMed.
  • Walker R D, Walshaw R, Riggs C M et al (1995) Recovery of two mycoplasma species from abscesses in a cat following bite wounds from a dog. J Vet Diagn Invest (1), 154-156 PubMed.
  • Beale K M (1995) Nodules and draining tracts. Vet Clin North Am Small Anim Pract 25 (4), 887-900 PubMed.
  • Kanoe M, Kido M, Toda M (1984) Obligate anaerobic bacteria found in canine and feline purulent lesions. Br Vet J 140 (3), 257-262 PubMed.
  • Ihrke P J (1984) Therapeutic strategies involving antimicrobial treatment of the skin in small animals. J Am Vet Med Assoc 185 (10), 1165-1168 PubMed.
  • Love D N, Jones R F & Bailey M (1979) Description of strains of Peptostreptococcus anaerobius isolated from subcutaneous abscesses in cats. J Gen Microbiol 112 (2), 401-403 PubMed.

Other Sources of Information