A small, unfamiliar growth on your dog can stop you in your tracks, especially when it seems to appear out of nowhere. If you have been wondering what causes skin tags on dogs, you are not alone, and a little knowledge goes a long way toward easing the worry.
Finding a bump during a petting session raises fair questions about whether it is a skin tag and whether it needs to come off. This guide explains what skin tags are, what is known about their causes, when a dog skin growth needs attention, how veterinarians tell growths apart, and what removal involves.
What Skin Tags on Dogs Are
Defining a Skin Tag
A skin tag is a small soft growth that extends from the skin on a narrow stalk. The medical term is acrochordon. MSPCA Angell describes these growths as usually the same color as the skin, formed from an overgrowth of connective tissue, and generally harmless. They range from a tiny projection to a growth several centimeters across and can move slightly when touched.
Skin tags are more common in older dogs, in certain breeds such as the Cocker Spaniel, and in areas where skin rubs against skin, such as the armpit. Collar and harness areas and skin folds are other places owners often find them.
How Skin Tags Differ From Other Growths
Many different dog skin growth types look alike on the surface. MSPCA Angell notes that 60 to 80 percent of canine skin masses are benign, which is reassuring but leaves a real share that are not. The table compares common growths using the sources listed below.
| Growth | Usual look | Benign or not | Key point |
| Skin tag | Soft, same color as skin, on a thin stalk | Benign | More common in older dogs and friction areas |
| Lipoma | Soft lump under the skin | Benign | Fatty tumor, usually in middle aged to older dogs |
| Papilloma | Wart like growth | Benign | A viral wart that can pass between dogs |
| Histiocytoma | Smooth raised bump | Benign | Common in dogs under about 3 and a half years and usually resolves in 2 to 3 months |
| Mast cell tumor | Varies widely | Can be malignant | Can swell and shrink and can look like a harmless lump |
Appearance alone cannot settle the question. Merck notes that mast cell tumors can mimic lipomas and that testing is needed to tell them apart.
What Causes Skin Tags on Dogs
What the Sources Support
MSPCA Angell links skin tag formation to an overgrowth of connective tissue and names three patterns: older age, certain breeds, and friction. Skin that rubs against skin or a collar is exposed to repeated irritation, which fits the places owners find them. Dogs with heavy skin folds can have more of these rubbing areas.
Online lists often add hormonal disease, parasites and diet as causes. The sources used for this guide do not connect those factors to skin tags, so they are not presented as causes here. A dog that develops several new growths at once, or shows other changes such as weight change or hair loss, needs an exam to look for a different explanation.
Irritation and Dog Skin Infections
A tag in a rubbing area can become sore if it is scratched, licked or caught by a collar. Redness, heat or discharge around a growth can point to dog skin infections and should be seen promptly. For background on how irritated skin is managed, see this guide on how to treat and prevent skin conditions in pets. Good overall care, including a diet suited to your dog’s age, supports skin health, and this blog on the benefits of nutritional counseling for pets at every life stage explains how that works.
When a Skin Tag Is Something to Worry About
Signs That a Growth Needs Veterinary Attention
Have a growth examined soon when any of these apply:
• It is new and has never been evaluated.
• Its size, shape or color has changed.
• It bleeds or has an open sore.
• Your dog scratches, bites or licks the area.
• It sits on a broad base and not a narrow stalk.
• Several new growths have appeared in a short time.
• It is near the eye, in the ear canal, on a paw pad or around the genitals.
• The skin around it is red, warm, swollen or draining, which can signal dog skin infections.
For a broader look at changes that deserve a visit, see this article on how to spot early signs of illness in your pets.
The Risk of Dog Tumors That Look Like Skin Tags
Some dog tumors imitate benign growths. The American College of Veterinary Surgeons reports that mast cell tumors make up 14 to 21 percent of skin tumors diagnosed in dogs and that their size can change from day to day as the cells release histamine. A mast cell tumor can sit quietly for weeks before it changes. The ACVS also states that a needle aspirate diagnoses a mast cell tumor in almost all cases, and that wide surgical margins are needed when one is confirmed.
Telling a skin tag from a malignant growth takes testing. This guide on what causes a skin growth in dogs and how to treat it explains how veterinarians evaluate and treat dog tumors.
How Veterinarians Evaluate Skin Tags
The Diagnostic Process
The visit starts with a physical exam and a history: when the growth appeared, whether it changed, and whether your dog has other signs. MSPCA Angell lists four options for a mass: a needle sample, a biopsy, removal with lab review, or careful monitoring.
Fine Needle Aspiration
A fine needle aspirate collects cells with a thin needle for review under a microscope. It is the usual first step for a new or uncertain growth.
Biopsy
A biopsy removes a small piece of tissue for a pathologist when the aspirate is inconclusive or the growth looks concerning.
Monitoring
A confirmed benign skin tag that causes no trouble can be monitored with periodic rechecks.
Treatment Options for Skin Tags in Dogs
When Removal Is Recommended
Many skin tags never need removal. Removal makes sense when a tag is repeatedly injured, becomes infected or inflamed, bothers your dog, sits near the eye, or leaves any doubt about what it is.
Removal is a short procedure. The area is clipped and cleaned, the dog is numbed or lightly sedated depending on the location, and the growth is cut off at its base. Sending removed tissue to a laboratory confirms what it was, a step MSPCA Angell lists among its options. For help with recovery, see this resource on how to keep your dog or cat comfortable after surgery.
Reducing the Risk of Skin Tags in Dogs
Practical Steps
Skin tags cannot always be prevented, but the factors above suggest sensible steps. Check that collars and harnesses do not rub, keep your dog at a healthy weight so skin folds rub less, and treat skin infections and itching promptly. Regular wellness visits let your veterinarian watch known growths and catch new ones early. This article on why preventive care for pets is crucial for early detection of health issues explains why routine checks matter.
What the Sources Cannot Tell You
No source reviewed here explains exactly why one dog grows a tag and another does not, and none ranks risk by breed beyond examples like the Cocker Spaniel. Percentages for benign and malignant masses describe groups of dogs, not your dog. Only a sample of your dog’s growth can say what it is.
Taking Skin Health Seriously
Skin tags are common in dogs and usually part of aging. Because some growths that look harmless are not, a new or changing dog skin growth deserves a veterinary check.
At Kainer Veterinary Hospital, our team evaluates growths with fine needle aspiration, biopsy and physical assessment so you know what each growth is. Whether a skin tag needs monitoring or removal, we will guide you through the right approach for your dog. Contact us today to schedule an evaluation.
Sources
MSPCA Angell, Benign Skin Masses of Dogs (accessed 2026). Veterinary teaching hospital clinical resource. Supports the skin tag description, the 60 to 80 percent benign figure and the diagnostic options.
Merck Veterinary Manual, Tumors of the Skin in Dogs (2018, updated 2026). Veterinary reference. Supports the lipoma, histiocytoma and mast cell tumor points.
American College of Veterinary Surgeons, Mast Cell Tumors (2024). Professional society. Supports the prevalence figure, day to day size change, aspirate diagnosis and wide margins.
FAQs
A: Skin tags form from an overgrowth of the skin’s connective tissue. Older age, friction in areas where skin rubs, and certain breeds such as the Cocker Spaniel are linked to them. The sources reviewed do not connect them to hormones, parasites or diet.
A: A true skin tag is generally harmless. The risk is that other growths, including mast cell tumors, can look similar. Any new or changing dog skin growth should be examined and sampled before it is assumed to be a skin tag.
Q: How can I tell a skin tag from a mast cell tumor?
A: You cannot tell reliably by looking. Mast cell tumors vary in appearance and can change size from day to day. A veterinarian takes a needle sample, which the ACVS says diagnoses a mast cell tumor in almost all cases.
Q: When should a skin tag be removed?
A: Removal is worth considering when a tag is repeatedly injured, infected, near the eye, bothering your dog, or uncertain in nature. A tag that is stable, comfortable and confirmed benign can often be monitored instead.
A: Not fully. You can reduce friction with well fitted collars and harnesses, keep a healthy weight, treat dog skin infections and itching early, and keep regular wellness visits so new growths are checked promptly.
