Dogs develop skin tags as they age primarily because of cumulative wear on the skin’s connective tissue. Over years of friction, minor inflammation, and normal collagen changes, small overgrowths of skin tissue form and protrude outward on thin stalks. These growths, called acrochordons, are almost always benign and become increasingly common in middle-aged and senior dogs.
What Happens Inside Aging Skin
A skin tag is essentially an overgrowth of the connective tissue in the skin’s deeper layer, the dermis. Under a microscope, skin tags are made up of tightly packed collagen bundles, active connective tissue cells called fibroblasts, and a network of small blood vessels. The outer layer of skin covering them tends to be thickened and sometimes darker than the surrounding coat area.
The exact trigger isn’t fully understood, but pathologists consider skin tags a proliferative response to low-grade, repeated inflammation. That inflammation can come from chronic friction, past minor trauma, or even a healed skin infection. Over a dog’s lifetime, these small insults accumulate. Younger skin repairs and remodels efficiently, but aging skin is slower to regulate tissue growth, making it more likely to produce these harmless excess structures rather than returning to a smooth baseline.
Friction, Folds, and Body Type
Skin tags tend to show up in areas where skin rubs against skin, such as the armpits, chest, and skin folds. This repeated friction creates exactly the kind of low-level irritation that prompts connective tissue to overgrow. Dogs that carry extra weight have more skin contact points and deeper folds, which increases the opportunity for friction-driven growths.
Certain breeds are genetically predisposed. Boxers, hound breeds, bully-type terriers, English Bulldogs, Pugs, and Cocker Spaniels all develop skin tags at higher rates. Many of these breeds share traits like loose skin, prominent folds, or naturally oily coats that create a microenvironment friendly to skin tag formation. That said, any breed can develop them, and mixed-breed dogs are not exempt.
Skin Tags vs. Other Growths
Not every bump on an aging dog is a skin tag, and telling the difference matters. Here’s how the most common benign growths compare:
- Skin tags are typically the same color as surrounding skin and hang outward from the body on a narrow stalk. They feel soft and move freely when you touch them.
- Sebaceous adenomas are small (usually under 1 cm), white to pink, with irregular borders. They sometimes secrete a greasy white material. These are overgrowths of oil-producing glands and are extremely common in older dogs.
- Viral warts (papillomas) are small, round, and have a rough, cauliflower-like surface. Unlike age-related skin tags, viral warts are caused by papillomaviruses and are actually most common in dogs under one year old. Most regress on their own within a few weeks to a few months.
The critical distinction is between any of these benign growths and something more serious like a mast cell tumor, which is the most common malignant skin cancer in dogs. Mast cell tumors often cause hair loss on the skin surface directly over them, and the overlying skin may change color. They can feel firm or rubbery rather than soft. A skin tag, by contrast, is floppy, skin-colored, and doesn’t cause hair loss in surrounding tissue. Because mast cell tumors are notoriously variable in appearance and can sometimes mimic benign lumps, visual monitoring alone is not reliable enough to rule them out.
When a Growth Needs Veterinary Attention
Veterinary oncology guidelines recommend that any skin or subcutaneous mass larger than 1 cm that has been present for a month should be sampled with a fine needle aspirate, a quick procedure where a small needle draws out a few cells for examination. Smaller masses can also be sampled, but they definitely should not be allowed to grow past the 1 cm mark without investigation. Growths that are rapidly increasing in size, changing in color or texture, or causing your dog irritation (excessive licking, scratching, or bleeding from being caught on things) also warrant a closer look.
Your vet may recommend a needle aspirate, a biopsy of a small piece of the growth, full surgical removal for a pathologist to evaluate, or a period of careful monitoring. The right approach depends on the size, location, and how the growth looks and feels.
Removal Options
Most skin tags don’t need to be removed. They’re painless and cosmetic. Removal becomes worthwhile when a skin tag is in a spot where it gets snagged on collars, harnesses, or furniture, or when it’s large enough to bother the dog.
Veterinary removal is straightforward. Cryosurgery, which uses extreme cold from liquid nitrous oxide to freeze and destroy the tissue, is one of the most common methods for skin tags. After cryosurgery, the frozen tissue sloughs off over about 7 to 10 days, and your dog may need to stay in an easy-to-clean area during that healing window. Surgical excision and electrocautery (using heat to cut and seal the tissue) are also options, particularly for larger skin tags with a significant blood supply.
Some of the larger skin tags develop a robust network of blood vessels inside them. Attempting to cut or tie off these growths at home risks significant bleeding and infection. Home ligation, where a thread is tied tightly around the base to cut off blood flow, does cause the tag to dry up and fall off in two to five days, but it carries real risks of pain, incomplete removal, and contamination. Veterinary removal with sterile instruments, proper disinfection, and the ability to control unexpected bleeding is a safer path, especially for any growth you haven’t had formally identified.
Living With Skin Tags on an Older Dog
If your vet has confirmed a growth is a benign skin tag, there’s no medical reason it needs to come off. Many senior dogs accumulate several over their lifetime and live comfortably with them. What does matter is keeping track. Note the size and location of each growth so you can detect changes. A simple method is to photograph them next to a coin for scale every few months. Any tag that starts growing noticeably, changes color, becomes firm, or begins bleeding deserves a new evaluation, even if it was previously confirmed benign.
Maintaining a healthy weight can reduce friction in skin folds and potentially slow the development of new tags, particularly in predisposed breeds. Regular grooming also helps you notice new growths early, when they’re small and easy to assess.