TL;DR: Swelling between a dog's toes is typically an interdigital furuncle requiring veterinary care within 24-48 hours, though immediate attention is needed if the swelling spreads or your dog has a fever.
What causes a red, painful lump or swelling between my dog's toes?
It is very common to feel worried when you notice a red, painful lump leaking pus between your dog's toes. This condition is most frequently an interdigital furuncle, often referred to as an interdigital cyst. These are deep-seated bacterial infections of the hair follicles that cause localized inflammation and abscesses. Other possibilities include a foreign body, such as a grass seed or splinter, or a reaction to an insect bite or sting.
Is a swollen lump between my dog's toes a veterinary emergency?
The urgency level for this condition is Medium. While a swollen toe with pus is rarely a life-threatening emergency, it is significantly painful for your dog and can lead to a systemic infection if left untreated.
- Schedule a veterinary appointment within 24 to 48 hours.
- Seek immediate veterinary care if your dog is unable to walk.
- Seek immediate care if your dog has a high fever or the swelling is rapidly spreading up the limb.
Why should I take a photo of my dog's paw for the veterinarian?
- Taking a clear, well-lit photo provides a vital tool for the veterinary team to assess the exact location and type of discharge.
- High-quality images allow professionals to determine the severity of inflammation and how quickly your pet needs to be seen.
- Visual information provides a baseline to track whether the swelling is improving or worsening after treatment begins.
Clinical Context (Merck Veterinary Manual)
Early lesions of interdigital furunculosis appear as focal or generalized areas of erythema and papules in the interdigital webbing, rapidly developing into single or multiple nodules, typically 1-2 cm in diameter, reddish-purple, shiny, and fluctuant; these may rupture upon palpation, exuding a bloody material. Interdigital furuncles are commonly found dorsally but may also be ventral, usually causing pain and lameness, with the dog licking and biting at the lesions. Differential diagnoses include traumatic lesions, foreign bodies, follicular cysts, and, rarely, neoplasia. Diagnostic tests should include skin scrapings for Demodex mites and impression smears or fine-needle aspirates to confirm inflammatory infiltrate. If bacteria cause interdigital furunculosis, there may be several nodules with new lesions developing as others resolve, with a common cause of recurrence being the granulomatous reaction to free keratin in the tissues.
Chapter: Dermatology
Source: The Merck Veterinary Manual, 11th Edition (Page 862)