Ulcerative pododermatitis, or bumblefoot, is a bacterial infection of the skin; specifically, the skin of the back feet and hocks -- the part of the back leg that rests on the ground when a rabbit sits. Because of the location and characteristic symptoms, this condition is also referred to as “sore hocks.”
If left untreated, ulcerative pododermatitis can deteriorate to include deep pyoderma -- severe inflammation with pus filled lesions, and deep cellulitis -- severe inflammation of the deep cellular and connective tissue. Exposure to harsh and wet surfaces, or moist surfaces which keep the tissue of the foot pads soft can predispose a rabbit to developing sores on the feet.
Once a deeper infection has set in, many other health conditions can arise in the rabbit. Synovitis (swelling of the joint tissues) often follows, progressing to osteomylitis (infection of the bone marrow), and mosteonecrosis, which results in the loss of blood supply to the bones, eventual bone tissue death and breakdown of the bones.
The signs and symptoms of ulcerative pododermatitis are usually graded from Grade I to Grade V, depending on the severity of the disease.
There are many causes for ulcerative pododermatitis, including pressure sores where the soft tissues of the limbs of the rabbit become lodged or trapped between bone and hard surfaces. Too much friction and exposure to constant moisture, especially on the hind feet, and exposure to urine or feces can also subject the feet to ulcerative pododermatitis, especially in animals with weakened immune systems or those that sit in soiled litter. Rabbits that are obese, or those that get too little exercise are at risk due to the amount of pressure placed on the foot surface, and/or the amount of time sitting in one place. Rabbits that thump their feet excessively are also at an increased risk of developing skin problems with the surface of the foot pad and hock.
Some rabbits develop ulcerative pododermatitis secondary to a bacterial infection, such as that caused by Staphylococcus aureus. Other common infections include Pasteurella multocida, Proteus spp., Bacteroides spp. or Escherichia coli.
Your veterinarian will need to rule out abscesses and infection that are associated with other trauma or fractures. X-ray imaging can provide detailed diagnostic images of the bones, allowing your veterinarian to determine how involved the bony structures in the body are, so that an estimate can be made for prognosis. Typically, rabbits with bone infections have a poorer prognosis and require longer treatment than those with milder stages of the disease.
An ultrasound examination can help rule out other causes for pain and discomfort as well, and can provide a better estimate of how extended the infection is, and whether it has invaded the surrounding skin, tissues and joint fluid.
A disease of the skin in which it emits pus
A medical condition in which the synovial membrane becomes inflamed
A product made of fluid, cell waste, and cells
A medical condition in which bone and bone marrow becomes inflamed
The digestive tract containing the stomach and intestine
A localized infection, usually a lesion filled with pus. Can be large or small in size.
The prediction of a disease’s outcome in advance