Many dog owners discover lumps or bumps on their dog’s body. While these can trigger concern, most skin growths in dogs aren’t emergencies. From soft fatty lipomas common in middle-aged or senior dogs to harmless button-like histiocytomas in younger pups, the majority are benign. Veterinary statistics show fewer than half of lumps on dogs are malignant.
Knowing the difference between a sebaceous cyst (essentially a canine pimple) and a mast cell tumor can prevent unnecessary stress and ensure the dog receives appropriate care when needed. Ultimately, a quick veterinary visit remains the best way to identify the type of growth and determine the right course of action.
What Types of Lumps And Bumps Are Most Common in Dogs?
Finding an unexpected lump on a dog can trigger immediate concern. Discovering a small bump on a dog’s side during regular grooming sessions is an experience many canine owners can relate to. Thankfully, most lumps that appear on dogs are non-cancerous, though some require proper veterinary attention.
Here are the most common types of lumps and bumps that dogs develop and what they might mean for a pet’s health:
Lipomas: The Common Fatty Tumors
Lipomas are frequently encountered lumps in middle-aged and senior dogs. These fatty tumors feel soft and rounded beneath the skin and can move freely when touched. While larger breeds like Labrador Retrievers are particularly susceptible, any dog can develop them, especially those carrying extra weight. Most lipomas grow slowly and remain harmless, though some can become large enough to interfere with movement if they develop near joints or in the armpit region.
Sebaceous Cysts: The Canine Equivalent of Pimples
These smaller bumps often resemble warts or pimples and form when oil glands are blocked. Sebaceous cysts are common in fine-haired breeds such as Poodles and Bichon Frises. If a cyst ruptures, a white, pasty discharge with a distinctive odor is noticeable. While generally harmless, these cysts can become infected if they break open, requiring antibiotics or surgical removal if they cause discomfort.
Warts (Papillomas): Common in Young Dogs
Caused by the papillomavirus, these cauliflower-like growths frequently appear in puppies and young dogs whose immune systems are still developing. Warts commonly form around the mouth, eyes, or paws and typically disappear on their own within a few months as the dog’s immunity strengthens. While contagious between dogs, these warts cannot spread to humans or other pets.
Skin Tags: Harmless Stalks of Tissue
Just like humans, dogs can develop skin tags—small, fibrous flaps of tissue that extend from the skin’s surface. These harmless growths are more common in older dogs and may appear anywhere on the body. They rarely cause problems unless they become irritated by collars, harnesses, or frequent scratching.
Abscesses: Painful Infection Pockets
Abscesses develop rapidly and cause noticeable pain. These pockets of pus form after bug bites, animal bites, or when foreign objects like grass awns penetrate the skin. An abscess feels hot to the touch, and the affected area is often protected by the dog. These require prompt veterinary attention for proper drainage, cleaning, and antibiotics to resolve the infection.
Histiocytomas: Button-like Growths
These red, button-shaped lumps typically appear on the legs of dogs under three years old. Histiocytomas result from an overproduction of immune cells and usually resolve on their own within two to three months. While benign, they can resemble more serious tumors, so veterinary confirmation is important.
Mast Cell Tumors: Requiring Quick Attention
These are among the most common skin cancers in dogs, particularly in breeds like Boxers, Boston Terriers, and Retrievers over eight years old. Mast cell tumors are challenging due to their variable appearance—they can resemble many other types of lumps. They may be firm or soft, raised or flat, and can change size dramatically in short periods. Any suspicious lump should be examined by a veterinarian, as early detection significantly improves treatment outcomes.
Other Concerning Lumps
Several other types of lumps require veterinary evaluation, including soft tissue sarcomas (firm masses in deep skin layers or muscle tissue), melanomas (pigmented skin tumors), and squamous cell carcinomas (often appearing in areas with lighter pigmentation or less hair). While less common than benign growths, these cancerous tumors highlight the importance of having all new lumps checked professionally.
How can you tell if a lump is a dangerous mast cell tumor or sarcoma?
Finding a lump on a dog can be alarming, but not all bumps are cause for concern. Some lumps might indicate serious conditions like mast cell tumors or soft tissue sarcomas. Knowing what to look for helps ensure timely action.
Common warning signs of dangerous lumps
While only a veterinarian can definitively diagnose a concerning lump, several characteristics may indicate a potentially dangerous growth:
- Rapid growth or sudden changes in size
- Firm or irregular texture that feels different from surrounding skin
- Redness, ulceration, or irritation of the skin over the lump
- Swelling or discomfort when the area is touched
- A previously stable lump that suddenly changes appearance
- Lumps that interfere with normal movement or seem to cause discomfort
Identifying mast cell tumors
Mast cell tumors rank among the most common skin cancers in dogs. They can mimic other skin conditions, typically appearing as:
- Raised, solid lumps that may be soft to firm when touched
- Masses that can fluctuate in size (sometimes growing larger and then smaller)
- Growths that may become red, swollen, or irritated after being touched
- Lumps that can develop anywhere on the body but commonly appear on the trunk, limbs, and between toes
Mast cell tumors are particularly challenging due to their microscopic reach, extending beyond visible areas and infiltrating normal skin tissue. Nearly 25% of dogs with mast cell tumors develop stomach ulcers due to histamine release from these cells.
Recognizing soft tissue sarcomas
Soft tissue sarcomas develop from connective tissues like muscle, fat, nerves, and blood vessels. These tumors often present as:
- Firm masses deep under the skin surface
- Lumps that feel attached to underlying tissues rather than freely movable
- Growths that may not cause pain initially but can affect mobility if located on limbs
- Masses that generally grow slowly but steadily over time
Soft tissue sarcomas can be deceptive because they often grow with tentacle-like projections into surrounding healthy tissue, making complete surgical removal challenging.
When should you see a veterinarian for squamous cell carcinoma, melanoma, or perianal adenoma concerns?
A good rule of thumb: any new lump warrants at least an initial veterinary assessment. Once confirmed as benign, most growths simply require monitoring for changes in size, appearance, or if they cause discomfort. Many harmless lumps come and go throughout a dog’s life without ever requiring treatment.
While perianal adenomas and certain types of warts may look alarming, they often pose little risk to a dog’s overall health. However, any growth that changes rapidly, changes appearance, ulcerates, bleeds, or seems painful or warm to the touch deserves prompt veterinary attention to rule out more serious conditions like melanoma or squamous cell carcinoma.
Diagnostic Process
A visit to the vet for a suspicious lump involves a thorough examination as appearance alone cannot determine if a lump is cancerous. The veterinarian will likely perform bloodwork, including a complete blood count and chemistry profile, to assess overall health. They may also conduct a urinalysis to check kidney and liver function.
Veterinarians use two primary methods to diagnose suspicious lumps accurately:
- Fine needle aspiration: A minimally invasive procedure where cells are extracted using a small needle and examined under a microscope. Often the first diagnostic step for most lumps.
- Biopsy: A more definitive procedure where a tissue sample is surgically removed for laboratory analysis. This may be necessary if fine needle aspiration results are inconclusive.
Imaging techniques such as X-rays, CT scans, or ultrasounds help determine if cancer has spread.
When Time Matters Most
Early detection significantly improves treatment outcomes. Regular home examinations—running hands through a dog’s coat during petting or grooming sessions—remain one of the best ways to detect new growths early. Pay special attention to areas beneath the collar, under legs, and around the mouth and eyes where lumps might be hidden by fur. This familiarity with a dog’s normal lumps and bumps helps making new growths easier to spot. Taking regular photos of suspicious lumps can help track changes and provide valuable information to the veterinarian.
Twice-yearly wellness examinations offer a chance for a veterinarian to monitor existing growths and identify new concerns. These regular check-ups complement at-home vigilance for a comprehensive approach to a dog’s skin health.
Don’t hesitate to contact a veterinarian if noticing:
- A growth that appears suddenly or grows rapidly
- Changes in the shape, color, or size of an existing lump
- Ulceration, bleeding, or discharge from a growth
- Signs of pain when the area is touched
- Behavioral changes like lethargy or loss of appetite
Lumps and Bumps on Dogs: Staying Proactive for Your Pet’s Wellbeing
Discovering new lumps on a dog can be worrying, but most skin growths are benign and manageable with early detection and regular checks. Combining gentle at-home examinations with timely veterinary assessments helps catch changes early and safeguards the dog’s health.
Tools that support proactive care—like the Halo Collar, which ensures dogs safely explore their environment—integrate those routine check-ins into daily life. This oversight complements veterinary guidance, offering greater peace of mind in caring for a dog’s skin health.
For more expert advice on keeping dogs healthy and happy, explore the Dog Health page today.
