Constantly licking and chewing their feet. Sore, red, itchy toes and lameness. Pododermatitis can be a real problem for our pets!
What is pododermatitis?
Pododermatitis is common in dogs. Quite literally, it means inflammation of the skin or footpads of the paws.
Dogs with pododermatitis usually exhibit paw licking or chewing and in more severe disease they may be lame, especially on hard ground. There are many causes of pododermatitis and it is important to get an accurate diagnosis and specific treatment. Otherwise it can be a cause of significant suffering if left undiagnosed or poorly managed.
Causes of pododermatitis in dogs
Many skin diseases and foot infections can cause pododermatitis. The common conditions are parasitic infestations, bacterial and yeast infections and allergies. Rarer causes include autoimmune diseases, congenital conditions, endocrine and metabolic disorders, and skin cancers. Disease may affect just the paws but more commonly involves other areas of the skin.
Demodicosis is a parasitic skin disease caused by a mite called Demodex canis. The mite is a normal inhabitant of the skin and lives in hair follicles. Mite numbers are kept under control by the immune system. Occasionally, for various reasons, mite numbers increase and this can result in a severe, inflammatory skin disease. Most commonly this is a generalised skin disease that can involve the paws although rarely only the paws are affected. Dogs with demodicosis will typically either lick or chew their paws and may be reluctant to walk on hard ground.
A Staffordshire Bull Terrier with demodicosis
The feet can become very inflamed and may show hair loss, redness, swelling, crusting and scaling. Demodicosis is the first disease your vet will consider when your dog presents with inflamed paws. The diagnosis is made by microscopic examination of hair plucks or skin scrapings from the paws although occasionally biopsy and histopathological examination are required.
This is a disease that can be treated, although it can take many months to achieve remission. Some dogs require long term therapy to prevent recurrence.
Bacterial and yeast skin infections are common in dogs and often involve the paws. Typically the skin between the toes and other skin folds are affected in yeast dermatitis with itching, redness, a greasy discharge, and sometimes brown discolouration of the nails. The signs of bacterial infections are very variable but may include itching, pain, redness, swelling, hair loss, crusting, draining sinuses and abscessation.
This photo shows the paw of a Great Dane with a deep skin infection
The bacteria and yeast involved are normal inhabitants of the skin and there is usually some underlying problem that provides an environment on the skin favouring the development of an infection. The most common underlying problem is atopic (allergic) dermatitis. Diagnosis of these infections is by cytology but culture and antibiotic sensitivity testing is often indicated when there is a bacterial infection. Cytology is a process of microscopic examination of samples taken from the skin; your vet will often use clear adhesive tape to take these samples.
Treatment options include shampoos, sprays and wipes. Occasionally antibiotics are required in cases where topical treatments are ineffective.
Atopic (allergic) dermatitis
Canine atopic dermatitis is a common, itchy, inflammatory skin disease that starts in young dogs and is usually associated with allergies to foods or environmental allergens. Signs of itching include scratching, rubbing, licking or chewing and the paws are frequently involved. Other areas similarly affected include the face, ears, limbs, flanks and abdomen.
This is the most common cause of foot licking and chewing. There is no single test that confirms a pet has atopic dermatitis. The diagnosis is based on history, examination and ruling out other itchy skin diseases. This is a disease that requires lifelong management but with the treatments available nowadays can usually be well managed and most dogs with this condition should have a good quality of life.
Other causes of pododermatitis
It is beyond the scope of this short article to discuss all the causes of pododermatitis but there are dogs where, despite a thorough and careful investigation, an exact cause cannot be identified.
In some of these cases, it has been suggested that poor foot or limb conformation may be a factor. This results in uneven weight distribution on the feet and weight is not borne entirely on the footpads but on haired skin between the pads. Hair shafts are then driven back into the skin resulting in deep skin inflammation, infection and abscesses that burst out on the upper surface of the paws between the footpads. Long standing disease of this sort can be debilitating and every attempt should be made to identify all the factors that contribute to the condition. A methodical systematic approach is required and this is where your vet may seek the opinion of a specialist dermatologist. Some cases may improve with prolonged antibiotic treatment but unfortunately disease often recurs even after improvement. Steroids and other anti-inflammatory drugs may be helpful in some cases and in those dogs where none of these treatments are helpful and they are suffering ongoing discomfort a surgical option called fusion podoplasty may be considered, which removes all the diseased and infected skin and restores weight-bearing onto the footpads.
In short, canine pododermatitis is a complex multifactorial condition. Unless the diagnosis is immediately obvious, your vet will need to carry out a careful, systematic investigation. The first step in any case of pododermatitis is to rule out the involvement of demodicosis. Cytology, cultures, biopsies, and blood tests may all be required. The aim is to make a specific diagnosis, and treatment may then be directed at the exact cause.