Skin Tags and Warts on Dogs: When to Worry

By Emiel Maddens  ·  Reviewed in consultation with licensed veterinary professionals  ·  Updated June 2026  ·  10 min read

Photo by Tima Miroshnichenko on Pexels

Finding a new lump or bump on your dog's skin can be unsettling. Many dog owners worry immediately about cancer, but the reality is that the majority of skin growths in dogs are benign. Skin tags and warts are among the most common benign growths veterinarians encounter, and understanding what they look like, why they form, and when they might signal something more serious can save you a lot of unnecessary anxiety while also ensuring you do not overlook a potentially dangerous change.

Skin tags, medically known as acrochordons or fibroepithelial polyps, are small, soft, pedunculated (stalk-like) growths that hang from the skin surface. Warts, or papillomas, are caused by the canine papillomavirus (CPV) and present as rough, cauliflower-like growths, most commonly around the mouth, lips, and eyelids of young dogs. While both conditions are typically harmless, they require different approaches to monitoring and management.

This article will help you distinguish between skin tags, viral warts, and other growths that may look similar. You will learn which growths can be safely monitored at home, which ones warrant a veterinary visit, and what treatment options are available when intervention is needed.

Understanding Skin Tags (Acrochordons)

What Are Skin Tags?

Skin tags are benign, soft tissue growths composed of a fibrovascular core covered by normal or slightly thickened epidermis. They typically appear as small, fleshy, pedunculated masses ranging from a few millimeters to a centimeter or more in diameter. Skin tags are attached to the skin surface by a narrow stalk (peduncle), which gives them a characteristic dangling or hanging appearance. They can occur anywhere on the body but are most commonly found in areas of friction, such as the axillae (armpits), groin, chest, and where collars or harnesses rub against the skin. The surface of a skin tag is usually smooth and may be the same color as the surrounding skin or slightly darker.

Why Do Dogs Develop Skin Tags?

The exact cause of skin tags in dogs is not fully understood, but chronic friction and irritation appear to play a significant role. Areas where skin folds rub against each other or where collars, harnesses, and clothing contact the skin are common sites for skin tag development. Older dogs are more prone to developing skin tags, and some breeds, particularly those with loose, wrinkled skin like Cocker Spaniels, Basset Hounds, and Bulldogs, seem predisposed. There is no definitive link to viral infection, sun exposure, or systemic disease, though some veterinary dermatologists have noted a correlation with obesity and insulin resistance in dogs that develop multiple skin tags. Genetics likely plays a contributing role, as some dogs develop numerous skin tags while others of the same breed and age develop none.

When Skin Tags Need Attention

Most skin tags never cause problems and can be left alone indefinitely. However, certain situations warrant veterinary evaluation or removal. If a skin tag is located in an area where it is repeatedly traumatized by movement, grooming, or collar contact, it may bleed, become inflamed, or develop secondary infection. Skin tags that suddenly change in size, color, or texture should be evaluated to ensure they are not being confused with a more concerning growth type. Any growth that becomes firm, rapidly enlarging, ulcerated, or attached by a broad base rather than a narrow stalk should be aspirated or biopsied to rule out neoplasia. While skin tags themselves do not become cancerous, their visual similarity to early-stage mast cell tumors or other skin neoplasms means that any questionable growth deserves professional assessment.

Canine Papillomavirus and Viral Warts

How Dogs Get Warts

Canine papillomaviruses (CPV) are a group of species-specific DNA viruses that infect the epithelial cells of the skin and mucous membranes. Dogs typically acquire the virus through direct contact with an infected dog or through contact with contaminated objects such as shared water bowls, toys, or bedding at dog parks, kennels, and daycare facilities. The virus enters through microscopic abrasions or disruptions in the skin or oral mucosa. After an incubation period of one to two months, characteristic papillomatous growths develop at the site of infection. Canine papillomavirus is not transmissible to humans or cats, so there is no zoonotic risk from affected dogs.

What Viral Warts Look Like

Classic viral papillomas appear as rough, irregular, cauliflower-like growths that may be white, gray, or flesh-colored. Oral papillomas, the most common type, develop on the lips, gums, tongue, palate, and pharynx, and can range from a single lesion to dozens of warty growths throughout the oral cavity. Cutaneous papillomas can appear anywhere on the body and may have a smoother surface than oral lesions. In young dogs with functioning immune systems, the papillomas are typically self-limiting and will regress spontaneously within one to three months as the dog mounts an effective immune response. Older dogs or those on immunosuppressive medications may develop persistent papillomas that do not resolve on their own and may require intervention.

Inverted Papillomas and Fibropapillomas

Not all papillomavirus-induced growths look the same. Inverted papillomas are a variant where the proliferating epithelium grows inward rather than outward, forming a cup-shaped nodule with a central pore. These are more commonly found on the ventral abdomen and groin region and typically occur in dogs between one and four years of age. Fibropapillomas have a larger fibrous tissue component mixed with the epithelial proliferation, giving them a firmer consistency. While both variants are benign, their unusual appearance can be concerning to owners and may prompt biopsy to confirm the diagnosis. Malignant transformation of papillomas is exceedingly rare in dogs but has been documented in cases of chronic, persistent lesions, particularly those associated with specific papillomavirus subtypes.

Treatment of Viral Warts

In the majority of cases, viral papillomas require no treatment because they will regress spontaneously as the immune system clears the infection. During the active phase, supportive care focuses on ensuring the growths are not interfering with eating, breathing, or comfort. If papillomas are causing mechanical problems, bleeding, or secondary infection, several treatment options are available. Surgical excision or cryotherapy (freezing) can remove individual problematic lesions. Crushing a papilloma to expose viral antigens to the immune system has been used as an autogenous vaccine approach. Oral azithromycin has shown efficacy in some refractory cases, possibly through immunomodulatory effects. Interferon therapy and imiquimod cream have also been used for persistent papillomatosis in immunocompromised dogs, though results are variable.

Regular veterinary examinations help distinguish benign growths from those that need further workup.

Photo by Tima Miroshnichenko on Pexels

Other Growths That Can Mimic Skin Tags and Warts

Sebaceous Gland Tumors

Sebaceous adenomas and epitheliomas are among the most common benign skin tumors in dogs and can closely resemble warts or skin tags. These growths arise from sebaceous glands and typically present as raised, lobulated, wart-like masses, often with a yellowish tinge and oily surface. They are most common in older dogs, with Cocker Spaniels, Poodles, and Miniature Schnauzers overrepresented. While these tumors are usually benign, sebaceous carcinomas (the malignant variant) do occur rarely and can be locally aggressive. Fine needle aspiration cytology can usually distinguish sebaceous tumors from other growth types and determine whether further intervention is needed.

Histiocytomas

Histiocytomas are benign tumors of immune cells (Langerhans cells) that are extremely common in young dogs, typically under three years of age. They present as small, firm, dome-shaped, pink or red, hairless nodules that appear suddenly and may initially grow rapidly. Owners and even some veterinarians may mistake them for warts due to their sudden appearance and relatively small size. Unlike warts, histiocytomas are not viral in origin and are not contagious. They typically regress spontaneously within two to three months as the immune system eliminates them. If a histiocytoma does not regress or continues to grow beyond three months, biopsy is recommended to confirm the diagnosis and rule out more concerning round cell tumors.

Mast Cell Tumors

Perhaps the most important reason to have any skin growth evaluated is the possibility of a mast cell tumor (MCT), the most common malignant skin tumor in dogs. Mast cell tumors are notoriously variable in appearance and can mimic almost any type of skin growth, including skin tags, warts, and insect bites. They may appear as small, soft, raised nodules that look completely benign, or as large, angry, inflamed masses. Any growth that fluctuates in size, has surrounding redness or swelling, or appears suddenly and does not resolve should be aspirated to rule out MCT. Fine needle aspiration is a quick, minimally invasive procedure that can be performed during a routine office visit and provides critical diagnostic information.

When to Biopsy or Aspirate

A general rule of thumb in veterinary dermatology is that any new growth should be evaluated rather than assumed to be benign. Fine needle aspiration (FNA) is the most common first-line diagnostic tool. Your veterinarian inserts a small needle into the growth, collects cells, and examines them under a microscope. FNA is fast, inexpensive, requires no anesthesia in most cases, and provides a preliminary diagnosis that guides further decisions. Full excisional biopsy, where the entire growth is removed and submitted for histopathology, provides a definitive diagnosis and is both diagnostic and therapeutic. A helpful monitoring approach for owners is to photograph growths monthly and compare images to track changes in size, color, and surface characteristics over time.

Monitoring Skin Growths at Home

The ABCDE Method for Dogs

Veterinary dermatologists have adapted the ABCDE screening method from human dermatology to help pet owners evaluate skin growths. A stands for Asymmetry, where one half of the growth looks different from the other. B is for Border irregularity, with uneven, scalloped, or poorly defined margins. C represents Color variation, where multiple colors (black, brown, red, white) within a single growth raise concern. D is for Diameter, with growths larger than one centimeter warranting closer attention. E stands for Evolution, meaning any change in size, shape, color, or texture over time. While this method is not a substitute for veterinary evaluation, it provides a useful framework for deciding when a growth needs professional assessment versus routine monitoring.

Documenting Growths with Photos

Photographing your dog's skin growths regularly is one of the most valuable things you can do for early detection of changes. Place a coin or ruler next to the growth for scale reference, and try to photograph from the same angle and in similar lighting each time. Many owners find it helpful to take photos monthly and store them in a dedicated album on their phone for easy comparison. When you visit your veterinarian, having a series of photos showing a growth's progression over weeks or months provides invaluable clinical information that a single snapshot cannot capture. Document the date, location on the body, and any observations about the growth's texture, firmness, and whether your dog seems bothered by it.

Creating a Body Map

For dogs that develop multiple skin growths over time, particularly older dogs, maintaining a body map can be extremely helpful. Sketch a simple outline of your dog's body and mark the location, approximate size, and date of discovery for each growth. This allows you and your veterinarian to quickly identify new growths versus known existing ones during examinations. Some veterinary practices maintain their own body maps in the patient record, but having your own home version means you can identify changes between veterinary visits. Digital body mapping apps designed for pet owners are also becoming available and can streamline the tracking process.

Red Flags That Require Prompt Evaluation

While most skin growths in dogs are benign, several features should trigger an immediate veterinary appointment. Rapid growth over days to weeks is more concerning than slow growth over months. Any growth that ulcerates, bleeds without trauma, or oozes discharge suggests a more aggressive process. Growths that are firmly attached to underlying tissue rather than freely movable may indicate invasive behavior. Multiple new growths appearing simultaneously could indicate a systemic process. A growth located on a digit, at a mucocutaneous junction (lip margin, eyelid, prepuce, vulva), or in the oral cavity carries a higher statistical risk of malignancy regardless of its appearance and should be evaluated promptly.

Treatment and Removal Options

Surgical Excision

Surgical removal is the most definitive treatment for skin growths that are causing problems or need histopathological diagnosis. For small, pedunculated growths like skin tags, excision is a straightforward procedure that can often be performed under local anesthesia or light sedation. The growth is removed at its base, and the wound is closed with a suture or left to heal by secondary intention if small enough. For larger or more complex growths, general anesthesia and wider surgical margins may be necessary, particularly if malignancy is suspected. The excised tissue is routinely submitted for histopathology, which provides a definitive diagnosis and confirms whether the margins are clear of abnormal cells.

Cryotherapy and Laser Removal

Cryotherapy involves applying liquid nitrogen to freeze and destroy abnormal tissue, and is a commonly used technique for removing small, superficial skin growths such as papillomas, small skin tags, and sebaceous adenomas. The procedure is quick, often completed in seconds per lesion, and can be performed in the exam room without general anesthesia. Some hair loss and temporary depigmentation may occur at the treatment site. Laser ablation using a CO2 laser is another option that allows precise tissue removal with minimal bleeding and good cosmetic outcomes. Laser treatment is particularly useful for growths in sensitive locations such as the eyelid margins or lip margins where traditional surgery may be more challenging.

When to Leave Growths Alone

Many skin growths, particularly confirmed benign ones such as skin tags, small sebaceous adenomas, and regressing papillomas, can be safely left alone and simply monitored. The decision to remove or observe a growth should balance the risk of the procedure (anesthesia, wound complications, cost) against the risk of leaving it in place. Growths that are not causing discomfort, are not in areas prone to trauma, and have been confirmed as benign through aspiration or biopsy are reasonable candidates for watchful monitoring. Your veterinarian can help you make an informed decision based on the specific growth type, location, your dog's age and health status, and your comfort level with ongoing monitoring.

Skin Tags and Warts on Dogs FAQ

Q: Are skin tags on dogs cancerous?

Skin tags (acrochordons) are benign growths and are not cancerous. They are composed of normal connective tissue covered by skin and do not have malignant potential. However, some cancerous growths, including mast cell tumors, can initially look similar to skin tags. If you are unsure whether a growth is a skin tag or something else, fine needle aspiration at your vet's office can quickly determine the nature of the growth and provide peace of mind.

Q: Can I remove my dog's skin tag at home?

No, you should not attempt to remove skin tags at home. Cutting, tying off, or pulling at skin tags can cause significant bleeding, pain, and infection risk. The skin tag's blood supply, though small, can bleed profusely when disrupted. Additionally, what appears to be a simple skin tag could be a different type of growth that requires proper veterinary handling. If a skin tag is bothering your dog or you would like it removed for cosmetic reasons, consult your veterinarian for safe surgical excision.

Q: Will my dog's warts go away on their own?

In most cases, yes. Viral papillomas (warts) caused by canine papillomavirus typically regress spontaneously within one to three months as the dog's immune system develops an effective response against the virus. Young, otherwise healthy dogs almost always clear the infection without treatment. However, dogs that are older, immunocompromised, or on immunosuppressive medications may develop persistent warts that require medical intervention. If warts have not begun to regress within three months, consult your veterinarian about treatment options.

Q: Are dog warts contagious to other dogs?

Yes, canine papillomavirus is contagious between dogs through direct contact or shared contaminated objects. The virus spreads most readily in environments where many dogs interact, such as dog parks, daycare facilities, and boarding kennels. However, healthy adult dogs with mature immune systems are often resistant to infection. Puppies and young dogs under two years of age are most susceptible. Canine papillomavirus is species-specific and cannot be transmitted to humans, cats, or other pets.

Q: How can I tell the difference between a skin tag and a mast cell tumor?

It can be difficult to distinguish between the two based on appearance alone, which is precisely why veterinary evaluation is so important. Skin tags are typically soft, pedunculated, freely movable, and stable in size. Mast cell tumors may appear as small, seemingly benign bumps but can fluctuate in size, develop surrounding redness, or change rapidly. The only reliable way to differentiate them is through fine needle aspiration, a quick, inexpensive procedure where your vet collects cells from the growth and examines them under a microscope.

Sources

Goldschmidt, M.H. & Hendrick, M.J. (2002). Tumors of the Skin and Soft Tissues. In Tumors in Domestic Animals, 4th Edition. Iowa State Press.

Lange, C.E. & Favrot, C. (2011). Canine Papillomaviruses. Veterinary Clinics of North America: Small Animal Practice, 41(6), 1183-1195.

Gross, T.L., Ihrke, P.J., Walder, E.J., & Affolter, V.K. (2005). Skin Diseases of the Dog and Cat, 2nd Edition. Blackwell.

Vail, D.M., Thamm, D.H., & Liptak, J.M. (2019). Withrow and MacEwen's Small Animal Clinical Oncology, 6th Edition. Elsevier.

Hnilica, K.A. & Patterson, A.P. (2016). Small Animal Dermatology: A Color Atlas and Therapeutic Guide, 4th Edition. Elsevier.

Related Reading

• Mast Cell Tumors in Dogs, The most common malignant skin tumor and why every lump should be checked
• Histiocytoma in Dogs, The benign bump that typically resolves on its own in young dogs
• Sebaceous Cysts in Dogs, Understanding epidermal inclusion cysts and when they need removal
• Monthly Skin Check Guide, How to systematically examine your dog's skin at home

Emiel Maddens

Founder of Vetified. Develops topical antifungal and antimicrobial formulations for companion animals. Vetified products are listed on DailyMed and manufactured through FDA-registered facilities in the United States.