Pododermatitis

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Pododermatitis in a dog[1]

Pododermatitis is a common inflammatory skin disease of the canine foot characterized by moisture-associated dermatitis, intertrigo and pyoderma.

Cutaneous disorders of the paw remain a challenging clinical entity and pododermatitis, although involving many possible causes, invariably appears uniformly similar clinically[2].

There are a number of recognized underlying causes of canine pododermatitis, including:

Various hypotheses have been proposed to explain the pathogenesis of idiopathic pododermatitis including pedal conformation, food allergy, trauma, immunosuppression, bacterial infection, furunculosis and dermal granuloma formation. However, many dogs display localized upregulated T- and B-lymphocyte responses within the skin lesions, and this may contribute to the pathogenesis of the skin lesions observed in many affected dogs[5].

Secondary bacterial infection is a frequent complication in lesional skin of affected dogs (particularly Staphylococcus pseudintermedius)[6].

Clinically affected dogs often present with symptoms such as lameness, pedal pruritus, erythema, swelling, pain and alopecia of the feet. The lesions produced in the pedal region are very varied in nature and can affect the digits, nails, interdigital space or pads. Close examination may reveal varying degrees of tumefaction, erythema, papules, saliva stain due to licking, hyperpigmentation, alopecia, nodules with serohaemorrhagic or purulent content, desquamation, crusts or fistulae.

As pedal lesions are reported in many canine dermatoses, a methodical series of diagnostic tests is required to establish the underlying aetiology. However, laboratory/ancillary investigations may prove unrewarding, prompting a diagnosis of idiopathic disease.

Diagnosis is usually confirmed on histopathologically, characterized by varying degrees of epidermal hyperplasia, hyperkeratosis, spongiosis, dermal oedema and perivascular aggregates of lymphocytes and plasma cells[7][8].

Skin scrapings and microbial cultures taken from the affected lesions are required to eliminate other possible differentials such as pyoderma[9] and Demodex spp infections.

Although non-responsive to antimicrobial therapy, antiparasitic agents and elimination diets, these dogs typically respond well to immunomodulatory therapy such as prednisolone, cyclosporin, tacrolimus or azathioprine[10].

References

  1. Purina Care
  2. Manning TO (1983) Cutaneous diseases of the paw. Clin Dermatol 1(1):131-142
  3. Breathnach RM et al (2008) A study of dendritic cell and MHC class II expression in dogs with immunomodulatory-responsive lymphocytic-plasmacytic pododermatitis. Vet J 177(3):352-359
  4. Kimmel SE et al (2003) Clinicopathological, ultrasonographic, and histopathological findings of superficial necrolytic dermatitis with hepatopathy in a cat. JAAHA 39:23–27
  5. Breathnach RM et al (2010) Cutaneous infiltrates and peripheral blood immune responses in dogs with immunomodulatory-responsive lymphocytic-plasmacytic pododermatitis. Vet Dermatol 21(4):383-392
  6. Breathnach RM et al (2011) Association between skin surface pH, temperature and Staphylococcus pseudintermedius in dogs with immunomodulatory-responsive lymphocytic-plasmacytic pododermatitis. Vet Dermatol 22(4):312-318
  7. Breathnach RM et al (2008) Canine pododermatitis and idiopathic disease. Vet J 176(2):146-157
  8. Breathnach RM et al (2005) Clinical, immunological and histopathological findings in a subpopulation of dogs with pododermatitis. Vet Dermatol 16(6):364-372
  9. Gortel K (2013) Recognizing pyoderma: more difficult than it may seem. Vet Clin North Am Small Anim Pract 43(1):1-18
  10. Duclos D (2013) Canine pododermatitis. Vet Clin North Am Small Anim Pract 43(1):57-87