Pododermatitis, Hock Sores, and Bumblefoot in Rabbits

What is pododermatitis?

Pododermatitis, also known as hock sores or bumblefoot, is a common health problem in pet rabbits. Some studies have found that up to 100% of pet rabbits are affected, though the vast majority are mildly affected. It is important to understand that wild rabbits do not develop pododermatitis – this is very much a condition that results from how we house rabbits in captive situations.

How does pododermatitis happen?

Rabbits do not have foot pads, unlike cats, dogs, ferrets, hedgehogs, and rodents. Instead, they have fur that covers the undersides of the feet in a sort of “comb-over” effect. This fur covers thin skin on the undersides of the feet, which in turn covers the bones of the foot with very little soft tissue in between. When a rabbit is standing on four feet, most of its weight rests on the hind legs. The tendon that travels along the bottom of the foot (the superficial digital flexor tendon) is held in constant tension, with the toes flexed. The weight of the rabbit should be distributed equally between the nails of the toes and the underside of the hock. In the wild, the rabbit’s nails sink into the grass or soil, allowing more even weight distribution and providing grip so they can spring forward at a moment’s notice, releasing the stored tension from the tendon. In captivity, we cannot easily replicate this sinking of the nails into the ground, so there is uneven distribution of weight between the nails and the hock. This leads to abnormal pressures being exerted on the hock both when the rabbit is at rest and when the rabbit is moving. Consequently, we see mild pododermatitis in almost all captive rabbits.

However, there are definitely factors that can make this pododermatitis worse. These can include:

• Small enclosures
• Limited exercise opportunities
• Poor nutrition
  • Obesity, emaciation, poor wound healing
• Pain
  • Spinal or joint pain, bladder or other abdominal pain, etc
• Chronic disease
• Limb abnormalities (loss or deformity)
• Excessive thumping
  • Anxious rabbit, stressful environment, incompatibility with other rabbits in household, territoriality
• Damp and/or dirty bedding; poorly absorptive bedding
• Incontinence
  • Urine or fecal scalding
• Inappropriate flooring
  • Hard, wire, or abrasive flooring (including carpet, towels, etc.)
• Overgrown nails
• Heavy body (large breed rabbits, especially >5 kg/11 lbs)
• Lack of guard fur covering undersides of feet
  • Rex type fur, or shaving the fur
• Increasing age

What are the signs of pododermatitis?

Because rabbits bear most of their weight on the back feet, this is where pododermatitis is primarily seen, though it can also affect the front feet. Early or mild stages of pododermatitis typically are seen at the point of the hock, and include fur loss, increased redness, and thickening and flaking of the skin (hyperkeratosis). As the condition progresses, it becomes increasingly painful for the rabbit. In more advanced stages the fur loss can become more extensive, encompassing the bottom of the foot towards the toes. The tissues of the underside of the foot can become thickened and swollen. The skin can become ulcerated and infected, as can other soft tissues, tendons, and even the bones of the foot. In severe cases, the tendons of the foot can become displaced and no longer functional, the skin and soft tissues can become necrotic (dead), and the rabbit can no longer use the foot. Treating pododermatitis, especially once it has reached advanced stages, is very challenging, and can require prolonged and intensive treatment. As such, our goal is to reduce the risk of pododermatitis in our pet rabbits as much as possible.

How Can You Reduce the Risk of Pododermatitis?

So, what can owners do at home to prevent/reduce the risk of advancing pododermatitis?

1. Keep the nails trimmed and do not allow them to become overgrown. This is very important because, as mentioned earlier, rabbits bear weight on their nails. When the nails are overgrown, they push up against the toe bones, causing even more abnormal pressure on the hocks.
2. Avoid hard or abrasive flooring. In an ideal world, our rabbits would be living on grass and soil, but that is not practical for many reasons.  Good substrate options include hay, recycled paper bedding, fleece, blankets, grass mats, foam floor squares, yoga mats, aspen shavings, etc.  Obviously, you will need to make sure that the rabbit is not eating the substrate you provide, and if they are you need to take steps to prevent that or try a different substrate.
3. Keep the rabbit and the environment clean. Dirty bedding does not wick moisture away from the rabbit.  Dirty bedding also harbors potentially harmful bacteria and fungi that can cause infections.  Rabbits who are incontinent may need extra cleaning, both of the environment and of themselves, to prevent complications from their condition.
4. Provide the rabbit with something thick and soft where they like to rest. This allows them to take weight off their feet, allowing blood circulation and healing.  In rabbits who have more advanced pododermatitis, special bedding like faux sheep skin (Sheepette) can be beneficial.
5. Provide your rabbit with appropriate nutrition. For many reasons, from dental health to gastro-intestinal health, to weight maintenance, the great majority of a rabbit’s diet should be high-quality grass hay (timothy, botanical, orchard grass, oat hay, etc.).  Pellets are a very concentrated food source that can be fed in limited quantities.  Rabbits who are fed excessive amounts of pellets will preferentially eat the pellets instead of hay and will tend to become overweight.  Obesity puts excessive weight on the feet and can also limit a rabbit’s ability to move around and to groom, increasing the risk of pododermatitis.
6. Have your rabbit evaluated by a rabbit-savvy veterinarian to evaluate for other predisposing problems. Health problems including spondylosis (bridging of bone between the bones of the spine), arthritis, obesity, emaciation, traumatic injuries, and incontinence can all increase a rabbit’s risk of developing/worsening pododermatitis.  As such, treating and preventing pododermatitis often involves identification and treatment of other underlying conditions.

With a few minor adjustments to your rabbit’s care, you can make a big impact on their long-term health and well-being, while significantly decreasing their risk of severe pododermatitis and the pain associated with this condition. I hope you have enjoyed this article and found it informative! Please let the editors know if there is another topic you would like me to discuss in a future column.

Dr. Teresa Bousquet, DVM, DABVP (Exotic Companion Mammal Practice)

Harvest Pointe Animal Hospital

Sources:
Varga-Smith, M. Skin Diseases, in: Textbook of Rabbit Medicine. Elsevier, 2023, pp 242-267

Mancinelli E, Keeble E, Richardson J, Hedley J. Husbandry Risk Factors Associated With Hock Pododermatitis in UK Pet Rabbits (Oryctolagus cuniculus). Vet Rec, 2014, Apr 26; 174(17):429. doi: 10.1136/vr.101830

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