What are the causes of pododermatitis?
There are many causes of this condition, with most of them being related to poor or inappropriate husbandry. More often, there are multiple causes, all ultimately leading to a decrease in blood circulation of the hind limbs, though occasionally it can be found in the forelegs. Here’s a list of some of the more common contributing factors;
- Poor hygiene – prolonged contact with wet and abrasive surfaces, especially if they’re contaminated with urine and faeces
- Surface – an inappropriate substrate may cause abnormal or excessive pressure on the sole. For example;
- wire flooring- this prevents the rabbit from walking or resting on its claws, so the weight is borne by the hock and metatarsus
- hard flooring - e.g. vinyl or concrete will prevent the claws sinking in to the substrate so most of the weight is taken by the hock and metatarsus
- Obesity - excessive weight will add additional contact pressure on ventral tissues
- Hair loss - absence of the protective hair in the metatarsal region. This may be from shaving or clipping
- Lack of exercise – restricted housing and insufficient play time
- Pain (e.g. spinal or dental pain) leading to immobility
- Pregnancy – a gravid female will become heavier and often less active
- Age – adults are more at risk than younger animals. This may be because they tend to be heavier and less playful
- Size - larger breeds have more problems than smaller breeds
- Injury – a major cause of pododermatitis is trauma
- Anxiety - regular thumping of nervous or stressed rabbits. The repetitive action can cause bruising and tissue damage
- Breed - Rex rabbits have feet padded with short soft fur that gives little protection
- Debilitating diseases – this will tend to make an animal less active, with its weight resting on the same tissues for prolonged periods
We tend to see this condition progress in stages, with it being harder to treat as the condition advances. Broadly speaking, we can divide it as follows;
- Phase 1 – look for signs of hair loss on the sole of the metatarsals and hock, with the skin developing epidermal hyperplasia.
- Phase 2 – the skin becomes tender and may show some signs of bleeding. There will also be further development of epidermal hyperplasia with parakeratosis.
- Phase 3 – the skin is usually thickened and hard. Pressure sores will be developing, and you may find infection and tissue necrosis.
Pododermatitis – the detail
Any condition that disrupts the normal cushioning of the foot may cause increased pressure on the plantar aspect, and eventually a pressure sore is formed. The consequences of this are numerous;
- Ischemia causes tissue necrosis
- An ulcer or abscess may form (ulcerative pododermatitis)
- Infection spreads to deeper tissues, lymph nodes and bone (osteomyelitis)
- Some animals will become incontinent
The condition is very painful and affected rabbits will avoid trying to walk which in turn reduces blood flow in the limbs. If a rabbit ends up developing osteomyelitis and synovitis, the tendons can be permanently damaged (the superficial digital flexor tendon can become displaced) so that it is no longer possible to maintain a normal stance and the rabbit will then sit back on its hocks permanently. In these cases, the damage is usually irreversible.
The increase in pressure being applied to the skin and soft tissues will result in ischaemia and necrosis. Secondary to this there will be;
- Bacterial infection
Lesions become infected
A deep pyoderma or cellulitis will inevitably lead to a chronic, non-healing condition. You’ll need to collect samples to culture and identify any bacterial involvement. Typical organisms found in the purulent white paste-like pus include;
- Staphylococcus aureus
- Pseudomonas species
- Escherichia coli
- Streptococcus species
- Proteus species
- Bacteroides species
- Pasteurella multocida
Action Plan for pododermatitis – 9 top tips
With the condition being multi-factorial, there are many things you can do to help, such as;
- Improve the environment – get an accurate picture of the home environment. Is the rabbit able to exercise? What bedding and flooring is provided? How often is the area cleaned and with what?
- Monitor weight – if the animal’s body condition and weight are high, develop a weight loss plan.
- Increase exercise – encourage the use of play areas and exercise time.
- Hair clip - the hair around the wound can be carefully assessed and if necessary, removed, but it must remain long enough to protect the rest of the foot.
- Clean the wound – use a safe product such as diluted povidone-iodine.
- Antibiotics - systemic and topical preparations can be used but be cautious to avoid those that cause enterotoxaemia. See our article on antibiotics in rabbits.
- Pain relief - analgesic (e.g. meloxicam) will help encourage the rabbit to move more which will help blood circulation.
- Physiotherapy - soft massages are generally enjoyed and helpful.
- Dressings – these must be changed regularly.