Pyoderma Figure 3

Figure 3: Pyoderma and abscessation.
Case history and photos


A 18-month-old female rat was brought to a more experienced rat keeper by the owner seeking advice on what appeared to be an abscess near the hip area. At the time, the abscess had been present for approximately six days.

Clinical Signs

When the abscess was lanced the wound was found to be filled with a gross amount of putrid smelling pus. The area was cleansed with Nolvasan, and the rat was taken to a veterinarian.

Initial Treatment

The vet debrided the wound and put the rat on high dosage Clavamox.

Within 12 hours a second abscess had developed right next to the first, and within another 12 hours tissue had become necrotic and bone was completely exposed. By the third day the rat was again brought back to the vet for more aggressive therapy.


Deep Pyoderma with abscessation.
Possible necrotizing fasciitis (“flesh eating disease”).

Etiology unknown, likely bacterial agent streptococcus spp.

Follow-up Treatment

On the return visit to the vet the third day, Baytril and doxycycline (massive dosages ) were given but no response was seen.


The rat developed bacteremia and sepsis and died within several days of the second vet visit. The vet indicated at this time that it was a “flesh eating type” of bacteria. The particular bacteria even ate the tissue so that there was not even a scab on the second abscess, and the hip joint was exposed. The first abscess had a eschar (or a black scab).


abscess, 6th day

Photo 1: Shows day 6 of abscess, and the first day treatment begun.
  abscess, 7th day

Photo 2: Shows day 7 of abscess, and the second day of treatment.

Photos 3 through 6 show the presence of eschar (pronounced “es kar”), gangrenous, sloughing tissue and advancing tissue destruction by bacteria.

eschar present

Photo: 3

Photo: 4

more deterioration

Photo: 5
  continuing deterioration

Photo: 6

*Notation: Although no histology was done, the vet supposed it to be a type of streptococcus spp. due to the speed and amount of tissue necrotized.

Case history and photos courtesy of Bellaratta’s Nest Rattery


Linked from


The Rat Guide and its affiliates accept no responsibility for misuse or misunderstanding of its information. This guide in whole or part, exists solely for the purpose of recognizing and understanding the care and illnesses in the pet rat. Please seek advice and treatment from a qualified Veterinarian if your rat is ill.

2000 - 2024 by Karen Grant RN. All rights reserved.
All other written and visual materials used by permission of specific authors for the sole use of the Rat Guide. Please visit our Privacy Policy for details.
Brought to you by KuddlyKorner4u
See Logos page for linking to the Rat Guide.
Contact us here: Rat Guide Team
Please note: Rat Guide email is not checked daily. Send e-mail to if you have an urgent medical problem with your pet rat. When possible, it is always best to take your rat to a qualified rat veterinarian.