Interdigital dermatitis is an inflammatory condition of the skin between the toes. It may be acute or chronic and can also involve the paw pads and the claw area. Affected dogs usually present with pruritus, swelling, erythema and pain in the paws (Duclos 2013).
Predisposing factors
- Anatomy: narrow interdigital spaces, hairy paws, conformational abnormalities
- Breed: commonly West Highland White Terriers, Scottish Terriers, Pekingese and English Bulldogs, also Labrador Retrievers and Boxers
- Obesity: mechanical load and reduced ventilation
- Moisture and maceration
- Underlying allergic disease: food allergy, atopy
- Endocrinopathies: hypothyroidism, hyperadrenocorticism
Aetiology
The condition is usually multifactorial. A primary cause is often present, followed by secondary infection. The skin may be primarily compromised by allergic dermatitis, foreign bodies or parasites (e.g. demodicosis). Bacteria (mainly Staphylococcus pseudintermedius) or yeasts (Malassezia spp.) then colonise the damaged skin (Díaz et al. 2023).
Clinical signs
- Erythema and swelling of the interdigital skin
- Pain, up to lameness
- Intense licking or chewing of the paws
- Exudation to purulent discharge, malodour
- Papules, pustules or nodules, up to draining tracts
- Hyperpigmentation, lichenification or fibrosis in chronic cases
(Horvath-Ungerboeck & van den Broek 2011)
Diagnosis
The aim is to identify the underlying causes. After clinical examination of the paw, basic diagnostics comprise:
- Cytology (tape or impression smear) to detect bacteria, yeasts and inflammatory cells
- Skin scrapings to exclude parasites
- Trichogram
Further blood and urine tests, allergy work-up and imaging are indicated as needed. Deep bacterial infection warrants culture with susceptibility testing.
Veterinary management
The approach depends on cause, severity and chronicity and rests with the veterinarian. It includes investigating and controlling the underlying disease, local measures, targeted medication in deep infection or yeast involvement, and protection against licking (e.g. a collar). In the wet season it is also sensible to keep the paws dry and clean, to trim the hair between the toes regularly and, where appropriate, to reduce weight.
References
- Díaz L, Castellá G, Bragulat MR et al. Study of the variation of the Malassezia load in the interdigital fold of dogs with pododermatitis. Vet Res Commun 47, 385–396 (2023). https://doi.org/10.1007/s11259-022-09951-2
- Duclos D. Canine Pododermatitis. Vet Clin North Am Small Anim Pract 43(1), 57–87 (2013). https://doi.org/10.1016/j.cvsm.2012.09.012
- Horvath-Ungerboeck C, van den Broek A. Pedal dermatitis in dogs and cats: Part 1. Companion Animal 16(1), 39–47 (2011). https://doi.org/10.1111/j.2044-3862.2010.00009.x