Sore hocks
(pododermatitis) in rabbits
Esther van Praag Ph.D.
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Pododermatitis is a skin disease
and a musculoskeletal problem, whose origin is multifactorial. Adult rabbits
are more often affected than young rabbits, larger breeds more than smaller.
The major cause is trauma, due to the pressure on the sole caused by running
on rough and/or abrading floors (e.g. rough carpets, tiles, vinyl or wire
flooring of cages), more rarely by regular thumping of anxious or nervous
rabbits. Poor hygiene in the cage can be a further cause for pododermatitis.
Genetics play a role too. Rabbits
belonging to the Rex breed have feet padded with short soft fur that brings
little protection. In Angora rabbits, shaved for their hairy coat, hair must
never be shaved away from the bottom of their feet. Some rabbits also have a
wrong physical body position. Instead of putting weight on the toes (rabbits
are digitigrades); they place weight on the metatarsus and hock. Others
position their hind feet wrongly, by stretching them too much to the front.
In both cases, an enormous pressure is exercised on the hock, leading to
pressure sores, ulcers and abscesses.
The various causes all lead to a
decreased blood circulation in the hind limb, more rarely in the forelegs.
Lack of oxygen supply (ischemia) causes tissue necrosis. A pressure sore is
formed, which can develop into an ulcer or an abscess. The infection spreads
to deeper located tissues, which can lead to the infection of the lymphatic
nodes, the bone (osteomyelitis), or general sepsis. At this stage, the
condition is very painful, and the rabbit will avoid walking, becomes
incontinent for both urine and feces. Reduced movement reduces proper blood
circulation in the limbs. A vicious circle is thus created, and the general
condition of the rabbit decreases rapidly.
In cases where the bone is
affected, the ligaments and the tendons can be displaced, which leads to
permanent invalidity. This condition is easily recognized by the special gait
of the rabbit, with a refusal to put pressure on its toes, and use of hocks
instead.
Diagnosis
It usually starts with a hairless
spot on the sole. The skin is thickened, inflamed and red, with necrotic
tissue in the middle of the wound. Ulcers and abscesses can be present. The
bacterial infection can be accompanied by the presence of purulent white
paste-like pus. If the wounds remain untreated, the infection will spread to
the inner tissues and can lead to the infection of the lymphatic system, the
bone (osteomyelitis) or general sepsis. The rabbit is usually restless, with
a decreases appetite and weight loss.
Clinical
signs
The
clinical signs and the behavior of the rabbit are usually enough for a proper
diagnosis. In the case of bacterial infection is present, cultures of samples
taken from the infected area can help confirm the presence of either Pasteurella
sp. or Staphylococcus aureus, but other bacteria have also been found.
It is thus highly recommended to do a bacterial cultured, accompanied by a
antibiotics sensitivity test. When
pododermatitis is left untreated, the condition will progress. ·
Stage 1:
alopecia on the sole, due to
compression of the hair follicles in the dermis, accompanied by a thickening
of the skin (epidermic hyperplasia and parakeratosis, or abnormal keratinization
of the skin). No bleeding is observed. ·
Stage 2: the skin is thick and shows epidermic
hyperplasia and parakeratosis. Small bleeding is observed. Appearance of a
callosity. The rabbit suffers pain at this stage. ·
Stage 3: naked, thick and hard skin, with crusty
hyper and parakeratosis. Pressure sores may develop. Necrotic tissue is
observed in the dermis. Healing is extremely difficult at this
stage.
Treatment
The treatment of pododermatitis needs to be on two levels: Find the cause of pododermatitis, which includes a thorough examination
of the environment where the rabbit is living and improve it, a reduction of
weight in case of obesity, accompanied by increased exercise possibilities. It is recommended to clip the hair around the wound, so that it cannot
reach the wound anymore but remains long enough to protect the rest of the
foot sole. The wound needs to be disinfected, e.g. with povidone-iodine,
after which a antiseptic cream can be used. Good results were obtained with
the following antiseptic products: - Salicylic acid 0.006%; - Mupirocin 2%; - Neomycin 2%; - Manuka honey; - HEALx cream; - Calendula/Echinacea 5% gel
(Powervet®, Switzerland). The use of systemic cephalosporin or azythromycin have proven
efficient in the treatment of abscesses that developed secondary to
pododermatitis. The antibiotic treatment should be done over a longer period
of time, eventually for lifetime. If pododermatitis is accompanied by pain, analgesic should be
administered to the rabbit, e.g., meloxicam, which can be used over a longer period
without appearance of side effects in rabbits. The reduction of pain usually
encourages the rabbit to move more, which is on its turn beneficial for the
blood circulation of the wounded leg. If this is not the case, soft massages
of the limbs can help activate blood circulation in the affected limbs. Bandaging the feet may be helpful. This can be by mean of a liquid plaster that produces
an impermeable layer while allowing breathing of the skin. Regular bandaging
material can also be used, but must be changed regularly to avoid infection. Rabbits are skillful bandage removers. It is therefore sometimes
useful to make a wire according to the size of the foot. This metal tube can
be filled with padding material, e.g. cork, in such a way that the wounded
area is left unperturbed and without pressure. Ulcerative
pododermatitis is often difficult to treat and recurrence is common.
Characterful, energy full rabbits may not
accept bandaging of a hind-foot easily. They fight and possibly try bite the hand or fingers handling them deeply, putting both
the rabbit and the handler/owner in danger. Especially when they are
bigger-sized rabbits. A new approach to treat pododermatitis is the use of a
custom made "rabbit sock". It has shown successful in the treatment
of paw lesions and pododermatitis in several rabbits already, reducing the
size of the wounds and leading to regrowth of the fur under the sole. For information on these socks, please
contact: info@medirabbit.com
MediRabbit
Benny wearing his rabbit sock, after injuring his
hind paw. Bandaging his foot was very difficult for him and the owner. Only after wearing his sock, the wound stopped
bleeding and started to heal.
For detailed information on pododematitis in
rabbits, by E. van Praag, A. Maurer and T.
Saarony, 408
pages, 2010.
Acknowledgement
A special thanks to Arie van Praag, Paula
Carter, Sandy Minshull, and Linda Baley, and Claudia Misceo for the pictures
of rabbits with pododermatitis. Thank you also to Flora, Bambi and Benny for
their patience.
Further
Reading
Jong IC, Reimert H,
Rommers JM. Effect of floor type on footpad injuries in does: a pilot study.
9th World Rabbit Congress, Verona, Italy. 2008, 1171-76. Drescher B,
Schlender-Boebbis I. Pododermatitis
(" Sore hocks") in the rabbit. Kleintierpraxis 1996:41: 99-103. Graham JE. Rabbit wound
management. Veterinary Clinics of North America: Exotic Animal Practice
2004:7:37-55. Harcourt-Brown F. Skin
diseases. In: Textbook of Rabbit Medicine. Oxford, UK:Butterworth-Heinemann;
2002 p 233-240. Henfrey J. Common
dermatoses of small mammals. In Practice 1993;15:67-71. Hermans K, Devriese LA,
Haesebrouck F. Rabbit staphylococcosis: difficult solutions for serious
problems. Vet Microbiol 2003;91:57-64. Hoppmann E, Barron HW.
Ferret and Rabbit Dermatology. Journal of Exotic Pet Medicine,
2007:16;225-237. Rommers JM, Meijerhof R.
1996. The effect of different floor types on footpad injuries of rabbit does.
In: Proc 6th World Rabbit Congress, Toulouse, France 1996;2:431-436. Rosenthal
KL. How to manage the geriatric rabbit. www.floridarabbit.org Accessed:
November 2008. |
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