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Bumps on Dogs’ Skin: 11 Reasons Why It Happens & Treatment

Bumps on dogs’ skin can be red, gray, black, white, or pink. They come in many shapes and sizes. These characteristics depend on the condition. Bumps on dogs’ skin can be warts, insect bites, benign tumors, cancer, blisters, hives, skin tags, and others. Contact the vet if your dog has bumps on its skin.

The skin is the largest organ and it is easily affected. Both internal factors, external factors, and irritating substances can lead to the appearance of bumps on dogs’ skin. 

It is important not to panic when your dog has a bump or lump on its skin and to contact the vet.

Bumps can be as harmless as an enlarged lymph node or acne, or they can be as bad as a cancerous tumor.

Bumps generally have different shapes, colors, and sizes depending on the condition. But there are cases where the conditions are confused with each other, such as benign tumors vs. cancer. 

In these situations, a visual examination of the dog is not sufficient for a precise diagnosis. An anatomopathological exam of the tumoral growth is also necessary.

In this article, you will learn what kind of bumps appear on dogs’ skin, what leads to their development, what to do, and more.

Why Does My Dog Have a Bump on Its Skin?

Bumps can be non-cancerous or cancerous. Most bumps are benign and non-cancerous, such as benign tumors, skin tags, blisters, or insect bites. It’s important to take your dog to the vet if you discover a bump or growth on its skin.

Bumps on the skin of dogs are usually divided into two categories:

  • Non-cancerous (benign)
  • Cancerous (malignant)

As for cancerous bumps, the only cause is cancer. On the other hand, non-cancerous formations can represent many things:

  • Acne
  • Sebaceous cyst
  • Insect bites
  • Hives
  • Skin tags
  • Benign tumors
  • Enlarged lymph nodes
  • Blisters
  • Warts

Most bumps and lumps on dogs’ skin are benign, so you don’t have to panic as soon as you see a formation on your dog’s skin. In rare cases, dogs (especially older ones) can develop several types of skin cancer.

It is important to take your dog to the veterinarian in time, especially if the bump or growth “appeared overnight”, is ulcerated, or bleeding. 

The earlier the diagnosis, the better the chances are for your dog if it has cancer.

Why Does My Dog Have a Bump on Its Skin

3 Types of Cancerous Bumps on Dogs’ Skin

Cancerous bumps are of three types: hemangiosarcoma, squamous cell carcinoma, and malignant melanoma. The symptoms of these generally include the appearance of bumps of different colors, sizes, and shapes on the skin. Symptoms also include pain, bleeding, weight loss, and others. 

Cancers are dangerous because they can migrate to other organs (metastasis) and cause dogs’ death. Malignant skin tumors are not extremely common in dogs and generally occur in older pets.

Here are the most common forms of malignant skin tumors in dogs where bumps develop on their skin:

  • Hemangiosarcoma
  • Squamous cell carcinoma
  • Malignant melanoma

These tumors are aggressive and spread quickly in the body, causing distant metastases (i.e. cancer cells spread to organs). 

This is how skin tumors end up destroying the organs and ultimately lead to dogs’ death.

If these tumors are diagnosed early, treatment can increase the odds of survival.

1. Cutaneous Hemangiosarcoma

Cutaneous Hemangiosarcoma

Cutaneous hemangiosarcoma is a skin tumor that occurs in medium-aged and old dogs. But, there are cases when it also occurs in dogs younger than three years. 

This cancer occurs in any breed, but some dogs are more prone to developing it:

  • German shepherd
  • Labrador retriever
  • The Golden Retriever

Large and giant breeds are also more affected by this type of tumor than small and toy breeds. Males are similarly more prone than females.

Two main factors that lead to the appearance of cutaneous hemangiosarcomas are prolonged sun exposure and UV rays.[1]

This type of cancer is characterized by the appearance of red bumps on dogs’ skin, which can ulcerate and cause bleeding.

2. Squamous Cell Carcinoma

Squamous cell carcinoma is a type of skin cancer that occurs due to prolonged sun exposure. It has an aggressive evolution, but metastasis (spreading) occurs slowly.

It generally appears in areas without hair:

  • Nose
  • Toes
  • Legs
  • Scrotum
  • Anus

The bumps on dogs’ that appear on the skin can be of three colors:

  • Red
  • White
  • Skin color

This type of cancer can ulcerate and bleed, like cutaneous hemangiosarcoma.

3. Malignant Melanoma

Malignant melanoma is a dangerous type of skin cancer because it is very aggressive and metastasizes quickly.

It can occur in any breed, but some breeds are more prone to developing it:

  • Schnauzer
  • Labrador retriever
  • Doberman pinscher
  • Vizsla
  • Terriers

Melanomas appear all over the dog’s body, but they are most often found as bumps on the mouth, gums, and lips. They appear less often in areas with hair.

Malignant melanoma is characterized by the appearance of black bumps on dogs’ skin.

8 Types of Benign Bumps on Dogs’ Skin

Benign bumps are harmless and are caused by many things, including acne, cysts, insect bites, hives, skin tags, and more.

Benign mainly means that a tumor, disease, or bump (growth) is non-cancerous. Other times, the term benign is attributed to conditions that are harmless.[2]

Benign growths do not invade the surrounding tissues and do not spread to other parts of the body as cancer does.

Here are the causes of benign bumps and lumps on dogs’ skin:

  1. Acne
  2. Sebaceous cyst
  3. Insect bites
  4. Hives
  5. Skin tags
  6. Benign tumors
  7. Enlarged lymph nodes
  8. Blisters
  9. Warts

1. Acne

Acne on dogs mouth

Acne is a medical condition where the hair follicles become irritated and inflamed. It commonly occurs in young dogs around puberty and in breeds with short hair.

There are five main factors that cause acne:[3]

  • Breed
  • Improper hygiene
  • Skin trauma
  • Hormonal status
  • Allergens

The most common symptoms of acne are as follows:

  • White or black small bumps on the chin, muzzle, and lips
  • Scaring
  • Lesions
  • Inflammation
  • Infection
  • Local pain

Acne disappears quickly if your dog is well cared for and proper treatment is applied.

2. Sebaceous Cyst

Sebaceous Cyst
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Sebaceous cysts look like small white bumps on dogs’ skin all over the body. These cysts contain a thick and oily substance known as sebum.

Sebaceous cysts can become infected and contain pus.

Treatment includes the following:[4]

  • Drainage of the infected cyst/surgical removal
  • Oral antibiotics (in severe cases)
  • Local ointments

3. Hives

Hives on dogs
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Hives appear when dogs come into contact with allergens, plants, or irritating substances, or when they are bitten by insects.[5]

It appears in different parts of the body and is characterized by the formation of small red itchy bumps. Some dogs will excessively scratch due to itchiness.

Hives usually resolve on their own without the need for treatment. In severe cases, skin infection occurs due to excessive scratching. If this happens, the vet may recommend oral antibiotics for the infection and anti-allergic drugs to calm the itching.

4. Skin tags

Skin tags on dogs
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Skin tags are harmless skin-colored bumps. They represent an excessive growth of the skin’s connective tissue and affect old dogs. 

These bumps occur where dogs’ skin rubs against itself the most, such as in the inguinal and axillary areas.

5. Benign Tumors

Benign tumors are usually pink or black bumps. They do not invade the surrounding tissues and do not spread in the body. 

They can appear in any area on the skin and affect all dogs, but old dogs are more prone.

The most common forms of benign skin tumors in dogs are as follows:

  • Melanocytoma
  • Histiocytoma
  • Mastocytoma
  • Hemangioma

6. Enlarged Lymph Nodes

Enlarged Lymph Nodes on dogs
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All dogs have lymph nodes. When they swell up, becoming enlarged, they look like small bumps on the skin. 

Lymph nodes can become inflamed and enlarged for several reasons:

  • Infections
  • Cancer
  • Local trauma

They appear as subcutaneous bumps (under the skin).

7. Blisters

Blisters generally appear when dogs come into contact with an irritating substance or plant. Dogs develop bumps with fluid (blisters), which cause pain when they burst. 

The most common areas of appearance are around the muzzle, abdomen, and legs.

8. Warts

dog Warts
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Warts (also called papillomas) are harmless benign tumors. They are caused by DNA papillomaviruses that have an incubation period of 1-2 months. They appear both on the mucous membranes and skin. 

In severe cases, mucous papillomas can spread to the esophagus, causing problems.

Papillomas usually resolve on their own 1-2 months after they appear.

Papillomatosis is a contagious disease that is transmitted to other dogs through direct contact or contaminated objects. They are cauliflower-like, irregular, and pedicled growths. They are pink, white, or gray.

About Iulia Mihai (DVM)

Dr. Iulia is a certified veterinarian with more than 10 years of experience in the field. With extensive knowledge of diet, care, and medication, she helps Misfit Animals provide readers with accurate knowledge on technical topics.

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