What is an interdigital cyst?
An interdigital cyst is an inflamed nodule that forms between your dog's toes. They most often appear on the front paws but can affect any foot. Technically called interdigital furuncles or interdigital follicular cystoids, they are not true cysts but inflammatory collections in the subcutaneous tissue of the interdigital space.
Common causes
- Bacterial follicular infection: the most frequent cause. Staphylococcus pseudintermedius infects the hair follicle, triggering a deep inflammatory reaction.
- Allergies (environmental or food): chronic itching leads to excessive paw licking, which disrupts the skin barrier and allows bacteria in.
- Trauma and foreign bodies: abrasive surfaces, splinters, sand or hot tarmac.
- Hormonal disorders: hypothyroidism is a known risk factor.
- Predisposed breeds: English Bulldog, Shar Pei, Labrador, Boxer, Bull Terrier and other short-coated or wrinkled breeds.
Symptoms
- Red, shiny or crusted lump between the toes.
- Limping or discomfort when bearing weight.
- Excessive licking of the affected paw.
- In advanced cases: ulceration, discharge or bleeding.
Treatment
- Soak baths (warm water with 2β4 % chlorhexidine): soften the tissue and encourage natural drainage.
- Systemic antibiotics: essential when infection is present; courses typically last 4β8 weeks to prevent recurrence.
- Corticosteroids or immunomodulators: if an allergy is the underlying cause.
- Surgery (marsupialization): reserved for chronic, treatment-resistant cases.
When to see the vet
Contact your vet if the lump has not improved after 5β7 days, if your dog is limping, or if the nodule ulcerates or weeps. Do not try to squeeze or lance the cyst at home β this can spread the infection.
Prevention
- Wash and dry paws thoroughly after walks in wet or muddy conditions.
- Inspect the interdigital space regularly, especially in predisposed breeds.
- Manage allergies with your vet to break the lick-infection cycle.
- Keep nails trimmed to reduce pressure on the interdigital area.