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Why Does My Dog Have Bumps? Understanding the Causes of Canine Skin Lumps - PawSafe

Why Does My Dog Have Bumps? Understanding the Causes of Canine Skin Lumps

Photo of Tamsin De La Harpe

Written by Tamsin De La Harpe

why does my dog have bumps

You may have noticed small bumps on your canine’s skin. While some of these swellings are harmless and may go away on their own, others can be a sign of a more serious issue. As a seasoned dog owner and trainer, I’ve seen my fair share of ups and downs when it comes to canine health. 

Recently, I’ve been navigating the world of bumps and lumps on dogs, something that many of us might encounter, especially as our canine companions enter their senior years. I’ve got two senior dogs myself, and they’ve had their own experiences with lumps on their throat and rectum, skin tags, and even an ear hematoma. It’s a journey that’s both concerning and enlightening, and I want to share what I’ve learned with you.

In this article, we’re going to dive into the topic of canine bumps, lumps, and skin issues. It’s a casual chat, but don’t worry, it’s backed up by some solid expert advice. We’ll be referring to insights from Dr. Hilary Jackson and Dr. Rosanna Marsella, renowned in the field of canine dermatology. Their work, detailed in the BSAVA Manual of Canine and Feline Dermatology, is a treasure trove of information that helps us understand what’s going on with our dogs’ skin.

Now, before we get into it, remember: finding a bump on your dog can be scary, but it’s not always a sign of something serious. Often, these lumps and bumps are just part of the aging process. However, it’s always better to be safe and informed, so let’s explore what these bumps could mean and how we can best care for our four-legged friends.

These bumps can range in size and texture and can be found anywhere on your dog’s body. While some of these protrusions may be harmless, others can indicate a more serious health issue. Our article on dog neck lumps focuses on swellings in that region, which may be particularly uncomfortable and dangerous to your dog.

If you notice that your dog’s bumps are growing rapidly, are bleeding, or have an unusual appearance, it’s important to take them to the vet for a thorough physical examination.

Understanding Canine Skin Lumps and Bumps On Dogs

Understanding the different types of skin lumps that can affect our dogs can help us determine the best course of action.

Types of Skin Swellings

Several different types of lumps can affect our dogs. These include:

  • Folliculitis: Inflammation of the hair follicle, which can result in small, raised regions on the skin.
  • Mast Cell Tumors: These are the most common type of lump in dogs, and can range in appearance from small, raised lumps to larger, more aggressive tumors.
  • Histiocytomas: These are benign tumors that often appear as small, raised lesions on the skin. They are most commonly seen in young dogs and tend to resolve on their own.
  • Lipomas: These are benign fatty tumors that can appear as soft, movable lumps under the skin.
  • Cysts: These are fluid-filled sacs that can appear anywhere on the body. They are usually benign and can be removed if they become bothersome.

13 Common Causes of Common Bumps and Lumps on Dogs

Swollen bumps on a dog's skin

When we notice lumps or tumors on our dogs, it can be concerning. Vin recommends a “see something, do something” approach to dealing with skin lumps in dogs. Therefore, even if you read a possible cause of your dog’s swellings here and it doesn’t sound dire, seek medical help.

Here are some common causes that could be responsible for those pesky skin protrusions:

1. Lipomas and Liposarcomas

Lipomas and liposarcomas are two types of fatty tumors that can develop in dogs.

Lipomas are benign tumors that grow slowly and do not spread to other body parts. Lipomas are usually soft and moveable and can be found just under the skin or deeper within the body. They are what PubMed refers to as “clinically unremarkable” since they’re relatively harmless. 

Conversely, Liposarcomas are malignant tumors that can grow quickly and spread to other parts of the body. They are typically firmer than lipomas and may be painful to the touch. Liposarcomas can also be found just under the skin or deeper within the body.

2. Hives

Hives, also known as urticaria, are a common cause of raised lesions and even rashes on a dog’s skin. Hives are typically raised, red, and itchy protrusions that can appear suddenly and spread rapidly. They are typically caused by an allergic reaction to something in the dog’s environment, such as food, medication, or insect bite.

If you suspect your dog has hives, it is crucial to identify and remove the allergen if possible. In some cases, antihistamines or corticosteroids may be necessary to manage the symptoms. Be sure to consult with your veterinarian before giving your dog any medication.

It is also important to note that hives can be a symptom of a more serious allergic reaction called anaphylaxis. Signs of anaphylaxis include difficulty breathing, vomiting, and collapse. If you suspect that your dog is having an anaphylactic reaction, seek emergency veterinary care immediately.

3. Warts and Skin Tags

Skin tag on dog's skin

Skin tags and warts are common in dogs and are usually benign. Skin tags are small, soft, and often hang off the skin. Warts, on the other hand, are small, hard, and often have a rough surface.

Skin tags are usually not a cause for concern unless they are irritated, infected, or growing rapidly. In these cases, it is best to consult with your veterinarian to determine the best course of action.

Warts, on the other hand, can be caused by a virus and can be contagious to other dogs. They can also be irritating and uncomfortable for your dog. Warts are a common reason for bumps on a dog’s lips. Treatment for warts can include cryotherapy, laser therapy, or surgical removal.

4. Acne

Acne is not just a problem for humans; dogs can also suffer from this skin condition. Acne in dogs is usually seen on the chin and lips, but it can also occur on the back, neck, and belly. It is more common in short-haired breeds and young dogs.

Acne in dogs is caused by the same factors as acne in humans: overactive oil glands, blocked hair follicles, and bacteria. Dogs with acne have small red pustules on their skin. These can be itchy and uncomfortable for your dog.

5. Sebaceous Cyst and Gland Tumors

Sebaceous cysts are common bumps that can appear on dogs. They are caused by a buildup of oil or sebum in the hair follicles. These can be small and unnoticeable, or they can grow to be quite large. Sebaceous cysts are usually not harmful to your dog, but they can become infected if scratched or if bacteria gets into the cyst.

Gland tumors are another type of bump that can appear on dogs. These tumors are caused by the overgrowth of cells in the glands that produce oil for the skin and hair. Gland tumors can be benign or malignant.

Cyst vs Tumor: Cysts happen when fluid fills a hollowed-out section of a dog’s body, while tumors occur when cells multiply for no reason.

6. Insect Bites

If you notice small bulges on your dog’s skin, it could be due to insect bites. Fleas, ticks, spiders, ants, and mosquitoes are common culprits that can cause this issue on your dog’s skin.

Flea bites are typically small, red, and itchy. They can cause your dog to scratch and bite at the affected area, leading to further irritation and potential infection.

Ticks can also cause inflammation on your dog’s skin. They can transmit diseases such as Lyme disease, so it’s vital to remove ticks as soon as possible. 

Mosquito bites can cause raised, itchy lesions on your dog’s skin. In addition to causing discomfort, mosquitoes can transmit heartworms, which can be a serious health concern for dogs.

7. Ingrown Hairs

Ingrown hairs are a common cause of skin lesions in dogs. Just like humans, dogs can get ingrown hairs when a hair follicle becomes clogged with dead skin cells, dirt, or other debris. This can cause the hair to grow sideways or curl back into the skin, resulting in a bump or pimple-like lesion.

Ingrown hairs can be caused by various factors, including poor grooming habits, allergies, and skin infections. Dogs with curly or wiry coats are also more prone to ingrown hairs, as their hair is more likely to become tangled and matted.

8. Interdigital Furunculosis

Interdigital furunculosis is a common skin condition that affects dogs. It is also known as interdigital cysts, pododermatitis, or toe cysts. This condition occurs when the hair follicles in the webbing between the toes become infected and inflamed, developing painful nodules or cysts.

The exact cause of interdigital furunculosis is not fully understood, but it is believed to be caused by a combination of factors, including bacterial and fungal infections, allergies, and trauma to the skin. MSD cites certain breeds, such as Bulldogs and Shar-Peis, as more prone to developing this condition.

Symptoms of interdigital furunculosis include limping, swelling, redness, and discharge from the affected area. Your dog may also lick or chew at the affected paw, and the skin may be warm to the touch.

9. Abscesses

If you notice a lump or bump on your dog’s skin that is red, swollen, and painful to the touch, it could be an abscess. An abscess is a localized infection when bacteria enter the skin through a wound or bite.

Abscesses can be caused by a variety of factors, including:

  • Bacterial infections;
  • Foreign objects, such as splinters or thorns that enter the skin;
  • Bite wounds from other animals; and
  • Ingrown hairs or clogged hair follicles.

If left untreated, abscesses can grow larger and become more painful. They may also rupture, causing the infection to spread to other parts of the body.

10. Hematomas

Hematomas are another common type of bump. Hematomas are pockets of blood that form under the skin, often due to trauma or injury. They can be painful and may cause your dog to lick or scratch the affected area.

Hematomas can occur anywhere on the body but are most commonly found on the ears. This is because dogs’ ears are thin and have a lot of blood vessels close to the skin’s surface. Hematomas on the ears can be particularly painful and may require medical treatment.

11. Collagenous nevi & Fibromas

Collagenous nevi and fibromas are two types of benign skin growths that can appear on dogs. Both are usually harmless and do not require treatment unless they become irritated or infected.

Collagenous nevi are small, firm, raised lumps that are typically pink or flesh-colored. They are caused by an overgrowth of collagen fibers in the skin. Fibromas, on the other hand, are soft, round, and often hairless growths that can vary in size. They are caused by an overgrowth of fibrous tissue in the skin.

12. Mast Cell Tumors

Mast cell tumors are the most common type of skin cancer in dogs. These tumors can appear as small, raised bumps on the skin and can be itchy or painful for your dog.

 Mast cells are a type of white blood cell that plays a role in the immune system, and when these cells become cancerous, they can multiply and form tumors.

13. Other Types of Skin Tumors

Tumors may sound like the end of the world for your dog. Luckily, tumor research shows that 60 to 80% of skin tumors are benign in dogs. So there’s a good chance you shouldn’t worry. However, medical attention is paramount to stave off the remaining 20%.

  • Benign, Nonviral, Wart-like Tumors: Some skin lumps can be benign, nonviral, wart-like tumors. These tumors are commonly found on the skin and are typically harmless.
  • Lymphoid Tumors of the Skin, or cutaneous lymphoma, are cancerous growths that develop in the lymphatic system. These tumors can appear as lumps on the skin and can be itchy or painful for your dog.
  • Smooth Muscle Tumors of the Skin, or leiomyomas, are a type of painless tumor that can develop in dogs. These slow-growing benign tumors show small, firm swellings on the skin that may be pink or brown. 
  • Tumors Originating Outside the Skin (Metastatic Tumors): Metastatic tumors are cancerous growths that originate in a different part of the body and then spread to other areas, including the skin. The most common types of metastatic tumors that affect dogs are breast, lung, and prostate cancer.
  • Basal Cell Tumors are typically slow-growing and benign. They are most commonly found on the head and neck of older dogs but can occur anywhere on the body. A study of 340 skin tumor cases found basal tumors to be the most abundant (26%). 
  • Blood Vessel Tumors are typically benign and can appear as red or black raised lumps on the skin. 
  • Melanomas are tumors that arise from pigment-producing cells in the skin. They can be benign or malignant and are often dark in color. 
  • Squamous Cell carcinomas are malignant tumors that arise from the cells in the outer layer of the skin. They often appear as raised, crusty, or bleeding masses on the skin and can be found anywhere on the body. Squamous cell carcinomas are more common in older dogs and those with light-colored skin.
  • Soft Tissue Sarcomas arise from the connective tissues in the body, such as muscle, fat, and cartilage. 
  • Cornifying Epitheliomas arise from the cells in the hair follicles. 
  • Hair Follicle Tumors are a group of tumors arising from the hair follicle cells. These tumors can be benign or malignant.
  • Histiocytic Cell Tumors: a group of malignant or benign tumors coming from immune system cells

Keep in mind that as dog’s age, they may get diseases like diabetes or Cushing’s disease. Both hormonal (endocrine) and immune diseases can cause growths in a dog’s skin.  In the picture below you can see the many lumps and bumps on an old dog with Cushing’s disease.

Bumps and lumps on the Belly of old dog with Cushing's disease

Symptoms to Watch Out For

When our dogs develop skin swellings, it can be concerning. As pet owners, we want to ensure our pets are healthy and happy. Here are some symptoms to watch out for:

1. Size and Shape

When examining your pet, take note of the size and shape of the protrusions. Are they small and round, or large and irregular? 

2. Color

The color of the lumps can also provide clues about their cause. Are they red, pink, or black? 

3. Texture

The texture can also provide important information. Are they soft and squishy or hard and firm? 

4. Location

The location can also provide important information. Are the lumps located on the skin or under the skin? Are they located in one area or spread throughout the body? 

Diagnosis of Skin Bumps in Dogs

Skin lumps are a common issue in dogs, and various factors can cause them. It’s essential to diagnose the cause of the bumps to provide the appropriate treatment. 

Here are some common methods for diagnosing skin bulges in dogs.

Physical Examination

The first step in diagnosing this issue in dogs is a physical examination. The vet will examine the size, shape, color, and location of the swellings. They will also look for other symptoms, such as itching, redness, or discharge. 

Biopsy and Histopathology

If the vet cannot determine the cause of the skin protrusions through a physical examination, they may recommend a biopsy. A biopsy involves taking a small tissue sample from the bump and examining it under a microscope. On the other hand, histopathology is the study of tissues under a microscope. 

Treatment Options

If your dog has skin lesions, seeking veterinary care to determine the underlying cause is essential. Once the cause has been identified, there are several treatment options available.


Depending on the cause of the inflammation, your veterinarian may prescribe medications to help alleviate symptoms or treat the underlying condition. 

For example, if an allergic reaction causes the issue, your dog may be prescribed antihistamines or corticosteroids. If a bacterial infection causes the lumps, antibiotics may be prescribed.

Surgical Removal

bandages on the skin of a dog whose bumps were removed by surgery

Your veterinarian may recommend surgical removal. This is typically done under anesthesia, and the bumps and a margin of healthy tissue are removed to ensure that all abnormal cells are removed.

Alternative Therapies

In some cases, alternativ-e-archive therapies may help alleviate symptoms or promote healing. These may include acupuncture, massage therapy, or herbal remedies.

 It is important to note that alternativ-e-archive therapies should only be used under the guidance of a licensed veterinarian.

Prevention and Care

Taking care of our canines is vital to ensure their health and happiness. Here are some preventive measures to keep your dog’s skin healthy and free from skin swellings:

Regular Check-ups

It is essential to take your dog to the vet for regular check-ups. The vet can identify any underlying health issues that may cause your dog’s skin inflammation. They can also recommend preventive measures and treatments to keep your dog healthy.

Proper Hygiene

Maintaining proper hygiene is crucial to prevent lumps on your dog’s skin. Regularly bathe your dog with a mild shampoo and conditioner to keep their skin clean and healthy. Make sure to dry them thoroughly after bathing, as moisture can lead to skin irritation.

Balanced Diet

A balanced and nutritious diet is essential for your dog’s overall health. A diet rich in vitamins and minerals can help prevent skin issues and keep your dog’s skin healthy. Consult your vet to determine the best diet for your dog’s specific needs.

When to Seek Veterinary Help

If you notice any lumps on your dog, monitoring them closely is important. If you notice any of the following, it’s time to seek veterinary help:

  • The node is rapidly growing or changing in size or shape;
  • Your dog is showing signs of pain or discomfort;
  • The swelling is bleeding or oozing;
  • Your dog is scratching or biting at the area; and 
  • The node is located in a sensitive area, such as the face or genitals.

In some cases, these skin protrusions can be a sign of cancer. Remember, early detection is key when it comes to treating cancer in dogs. If you notice any new or unusual tumors on your dog, don’t hesitate to make an appointment with your veterinarian.

Frequently Asked Questions (FAQs)

How can I treat bumps under my dog’s fur?

If your dog has lumps under their fur, it’s best to take them to a veterinarian for a proper diagnosis. The treatment will depend on the underlying cause. Sometimes, the vet may recommend antibiotics, antifungal medications, or topical creams. In more severe cases, surgery may be necessary.

Why do dogs get sudden lumps under their skin?

There are many reasons why dogs may develop sudden lumps under their skin. These can include allergic reactions, insect bites, infections, tumors, or cysts. It’s essential to have any new lumps checked by a veterinarian to rule out serious health concerns.

What could be causing pimple-like bumps on my dog?

A bacterial or fungal infection, allergies, or insect bites may cause pimple-like pustules on your dog. Your vet may recommend antibiotics, antifungal medications, or topical creams to treat these swellings.

What are some treatments for sebaceous cysts in dogs?

Sebaceous cysts are common in dogs and can be treated by draining the cyst or surgically removing it. Your vet may also recommend antibiotics or topical creams to prevent infection.

Are little bumps under my dog’s fur something to worry about?

Not all pustules under your dog’s fur are cause for concern. Some may be harmless cysts or lipomas, while others may be more serious. It’s essential to have any new lumps checked by a veterinarian to ensure your dog’s health and well-being.

How can I get rid of bumps on my dog’s skin?

The treatment depends on the cause. Your vet may recommend antibiotics, antifungal medications, or topical creams. In some cases, surgery may be necessary to remove the bump. It’s essential to consult your vet to determine the best treatment for your dog.


A variety of factors can cause bumps in your dog. It’s essential to monitor any changes in your dog’s skin and behavior. If you notice any new skin bulges or changes in your dog’s behavior, it’s essential to consult with your veterinarian.

Some common causes of dog lesions include allergies, insect bites, and infections. This inflammation can sometimes be a sign of a more severe condition, such as cancer. It’s important to have any new growths on your dog checked by a veterinarian.

Meet Your Experts

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Tamsin De La Harpe


Tamsin de la Harpe has nearly two decades of experience with dogs in rescue, training, and behavior modification with fearful and aggressive dogs. She has worked closely with veterinarians and various kennels, building up extensive medical knowledge and an understanding of canine health and physiology. She also spent two years in the animal sciences as a canine nutrition researcher, focusing on longevity and holistic healthcare for our four-legged companions. Tamsin currently keeps a busy homestead with an assortment of rescue dogs and three Bullmastiffs.

Tamsin de la Harpe has nearly two decades of experience with dogs in rescue, training, and behavior modification with fearful and aggressive dogs. She has worked closely with veterinarians and various kennels, building up extensive medical knowledge and an understanding of canine health and physiology. She also spent two years in the animal sciences as a canine nutrition researcher, focusing on longevity and holistic healthcare for our four-legged companions. Tamsin currently keeps a busy homestead with an assortment of rescue dogs and three Bullmastiffs.