Page 274 - WSAVA2017
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An Urban Experience
 Erythema: Diffuse on both interdigital surfaces Plantar surfaces only Focal or macular-papular
 Atopic dermatitis and/or adverse food reaction Contact dermatitis Infection; Demodex
  Follicular casts & comedones
  Demodex Weight bearing on haired skin & ingrown hairs
  Single paw/digit
  Trauma, foreign body, neoplasia, acral lick granuloma, abnormal conformation
  Uneven pad or nail wear
   Altered conformation and/or weight bearing
  Interdigital furunculosis & sinus tracts
    Infection, foreign body reaction
  Conjoined pads & new pad formation Deep tissue pockets Scar tissue
  Chronic pathological changes
  Joint pain & reduced range of movement
  Saliva staining
   Licking; pain or pruritus
 Self-induced alopecia Spontaneous alopecia
 Pruritus Demodex; dermatophytosis; endocrine
Hair plucks, skin scrapes and impression smears should be taken to rule out Demodex, but histopathology may be required in chronic cases. Histopathology can also achieve a definitive diagnosis of chronic pododermatitis. Impression smears should be used to confirm bacterial and/or Malassezia infection, but bacterial culture and sensitivity is mandatory if there is deep infection, and/or multiple antibiotic courses. Samples can be taken from ruptured pustules or draining sinus tracts, but biopsy is often necessary to isolate organisms from deep tissues.
If a foreign body or tumour is suspected, radiographs of the feet possibly with abdominal ultrasound may
be appropriate. Haematology, serum biochemistry, thyroid tests and urinalysis should be performed if systemic disease is suspected. Regional lymph nodes are frequently enlarged due to local inflammation but lymphoma should be ruled out. Fungal culture and faecal analysis can be performed if dermatophytosis or hookworm are suspected. Further investigations may include a diet trial and intradermal or serological allergy testing.
Management of primary and predisposing factors
Management of the primary and predisposing triggers for the pododermatitis is crucial for successful long term control. In our clinic, the most common primary conditions are atopic dermatitis and adverse food reactions.
Obesity is a common predisposing factor. Pododermatitis is more common in the forelimbs, which bear approximately 60-70% of bodyweight. Excess weight also exacerbates changes in limb conformation and weight bearing surfaces. Management of pain, altered weight bearing and abnormal conformation could include analgesia and/or corrective surgery. Protective boots (e.g. Ruff Boots®) can be helpful, especially in dogs reluctant to exercise due to pain. Regardless of the cause, chronic inflammation, deep pyoderma, split pads and non-healing wounds can be very painful. Prompt analgesia and boots should be considered in all cases.
Control of secondary infections
Systemic antimicrobial therapy
Systemic antibiotics should be selected using culture and sensitivity. Treatment may take 4-6 weeks. Scar tissue can inhibit the penetration of water soluble antibiotics (e.g. penicillins and cephalosporins) and antibiotics (e.g. clindamycin or fluoroquinolones) with good penetration into scar tissue are beneficial.
Dogs with a staphylococcal hypersensitivity or recurrent infections may benefit from Staph Phage Lysate (SPL®). This could induce tolerance to staphylococcal proteins and/or enhance anti-staphylococcal immunity.
Some cases of Malassezia overgrowth require systemic antifungal therapy, especially with Malassezia hypersensitivity. Options include intraconazole, ketoconazole or terbinafine. Allergen specific immunotherapy with Malassezia extracts can be beneficial.
Topical antimicrobial/antifungal therapy
Daily cleaning of the paws is ideal, but the frequency can be reduced for maintenance. Owners should be shown how to spread the digits and thoroughly clean deep pockets or sinus tracts. Chlorhexidine is a highly effective antimicrobial but requires a 5-10 minute contact time. Chlorhexidine wipes are easier to use, but have no residual activity and are not effective against Pseudomonas. Hypochlorous acid is a safe and potent antimicrobial, but has no residual effect.
Topical antibiotics are often highly effective, but penetration can be variable and they are less suitable for deep infections. Useful antibiotics include fusidic acid, silver sulfadiazine (which can be combined with gentamicin or marbofloxacin), neomycin or polymyxin B. Many products also contain a steroid (see below).

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