A cyst on a dog’s paw typically appears as a raised, red nodule between the toes, ranging from a small bump to a shiny, reddish-purple boil about 0.4 to 0.8 inches (1 to 2 cm) across. These growths, most accurately called interdigital furuncles, are filled with blood, pus, or a mix of both. They’re one of the most common paw problems in dogs, and while they can look alarming, understanding what you’re seeing helps you figure out how urgently your dog needs veterinary attention.
What Paw Cysts Look Like at Each Stage
These growths change appearance as they progress. In the earliest stage, you’ll see rash-like redness and small bumps in the webbing between your dog’s toes. The skin in that area may look pink or irritated, similar to a mild rash. At this point, the bumps are easy to miss unless you’re actively checking your dog’s feet.
If left untreated, those small bumps develop into firm, shiny, reddish-purple boils. They’re usually round, raised, and may feel firm or slightly squishy depending on how much fluid has built up inside. Some cysts have open, draining wounds that leak bloody or pus-like discharge. Others remain closed but visibly swollen. The surrounding skin is often moist, hairless, or both, partly from infection and partly because dogs tend to lick the area obsessively.
In more advanced cases, the entire paw can become grossly swollen. The toes may look splayed apart from the pressure of the swelling between them. You might also notice the skin between the toes is ulcerated or raw. Some long-standing cysts eventually harden into painless scar tissue from repeated flare-ups, at which point they feel firm and aren’t tender to the touch.
Where Cysts Usually Appear
The front paws are affected far more often than the back ones. The most common location is the outer webbing between the fourth and fifth toes (the two smallest toes on the outside of the paw). However, cysts can develop between any of the toes, and some dogs get them in multiple spots at once. They almost always form in the webbed skin between the toes rather than on the paw pads themselves, though the surrounding pad tissue can become inflamed in severe cases.
How Your Dog Will Act
Behavior changes are often what alert owners to paw cysts before they actually see the growth. Dogs with interdigital cysts frequently lick and chew at the affected paw, sometimes to the point of staining the fur with saliva. Limping is common, especially on hard surfaces, since the cyst sits in an area that bears weight with every step. Some dogs will shift their weight noticeably or refuse to walk on certain terrain. If a cyst ruptures, the pain can intensify, and you may notice bloody fluid on floors or bedding.
What Causes Them
The most common cause is a deep bacterial infection in the hair follicles between the toes. Short, bristly hairs in the webbing can break off and become embedded in the skin, where they trigger an inflammatory reaction. The body treats these trapped hair fragments like foreign objects, walling them off and creating the characteristic boil. Secondary bacterial infections pile on top of that inflammation, making the cyst larger and more painful.
Allergies are another major driver. Dogs with environmental allergies or food sensitivities tend to lick their paws, and that repeated moisture and trauma to the skin creates the perfect conditions for cysts to form. Mites, hormonal conditions like an underactive thyroid, and chronic skin barrier problems can also predispose dogs to these infections.
Certain breeds are especially prone. Labrador Retrievers, English Bulldogs, Chinese Shar-Peis, German Shepherds, and Pekingese all have higher rates of interdigital cysts. The common thread is either prominent webbing between the toes, short bristly hair in that webbing, or wide paw shapes that force the dog to bear weight on the haired skin between the pads rather than just the pads themselves.
Cyst vs. Tumor: Why You Can’t Tell by Looking
This is the most important thing to understand about any lump on your dog’s paw. Several types of tumors can appear in the same location and mimic the look of a cyst. Mast cell tumors, for instance, can appear as raised lumps that feel soft or firm and vary widely in size. They can look nearly identical to a benign cyst. Histiocytomas show up as solitary, raised, hairless bumps that are most common on the limbs. Melanomas can appear as raised, sometimes ulcerated masses with dark pigmentation.
Sweat gland tumors are rare but do occur specifically on paw pads, and when they develop, they tend to be aggressive. Even experienced veterinarians cannot distinguish a benign cyst from a cancerous growth based on appearance alone. The only reliable way to tell the difference is by examining cells under a microscope, either through a fine needle aspirate (where a small needle draws out cells from the lump) or a tissue biopsy. If you find any new lump on your dog’s paw, getting it checked is the only way to rule out something serious.
How Paw Cysts Are Treated
Treatment depends on the severity and the underlying cause. For mild cases, topical treatments applied directly to the cyst may be enough. More serious or deep infections typically require oral antibiotics, sometimes combined with anti-inflammatory medication. If mites are involved, a targeted antiparasitic treatment is used. When allergies are the root cause, the cysts will keep coming back until the allergy itself is managed, which is why identifying the trigger matters as much as treating the bump.
Warm foot soaks can help at home, both for comfort and to keep the area clean. A common approach is dissolving a cup of Epsom salts in a gallon of warm water and soaking the paw for about 10 minutes. Diluted iodine dips (mixed to the color of weak tea) used for 30-second soaks can also help manage bacteria on the skin’s surface. These aren’t substitutes for veterinary treatment when a cyst is actively infected, but they can support healing and help prevent recurrence between flare-ups.
For dogs with chronic, recurring cysts that don’t respond to standard treatment, laser removal of the affected tissue is sometimes recommended. This is typically reserved for cases where scarring and repeated infection have made the tissue permanently prone to new cysts.
Preventing Recurrence
Because interdigital cysts so often come back, prevention matters as much as treatment. Keeping the fur between your dog’s toes trimmed short reduces the chance of hairs breaking off and embedding in the skin. Rinsing or soaking paws after walks, especially on dirty or rough terrain, helps remove debris and bacteria before they can cause problems. For dogs with known allergies, managing the underlying allergy through diet changes or allergy treatment is the single most effective way to stop the cycle. Keeping paw skin dry (but not cracked) between the toes also discourages the moist environment that bacteria thrive in.