Dog Lumps on Skin

"Dog lumps on skin can have many causes. The diagnosis will dependon an understanding if the lump has changed over time, the look and feel and if it is interfering with the quality of your dog's life. Treatment is dependent on the type of lump and if surgery is necessary."

There are many causes of dog lumps on skin. The lumps are due to some type of fluid accumulation.

Lumps generally fall into two categories:

Benign Lumps (not cancer) - characteristics of these lumps are no or slow growth. It is possible that they will not change or take years to change.

Malignant Lumps (cancerous) - These lumps may grow quickly and spread into the skin.

According to Dr. Timothy Fan, your veterinarian will ask several questions about the dog lumps on skin or bumps:

1. Has the lump appeared suddenly, or has it been there awhile?
2. Has the lump stayed the same in consistency and appearance or has it changed recently?
3. Does the lump seem to separate from underlying tissue or is it attached?
4. Is there only one lump or have you found multiple similar lumps?
5. Are there changes in your dog's behavior such as eating less, losing weight, vomiting, diarrhea, or lethargy?

Types of Dog Lumps on Skin

Abscess � this is a cavity in the skin filled with pus.Abscesses are caused by infections, very rarely they can form at the sites of an injections.

Lipoma - lipomas are fatty lumps on the skin that are often seen in middle aged, overweight female or older dogs. They tend to appear on the belly and upper legs. Lipoma's are usually seen in Schnauzers, Labs, Domermans and mixed breeds. It is rare for a lipoma to be cancerous.

Mast cell tumor - These cells are used by the body to defend against outside elements that enter your dogs body. For example, an insect bite causes swelling on the skin because of these cells. If the normal mast cell undergoes a malignant change, a mast cell tumor may be produced. Mast cells can be malignant or benign.

Picture of Mast Cell Tumor

Picture of Dog Lump on Skin Mast Cell Tumor

Neoplasia Nodule � a firm, solid cutaneous swelling up to 1 cm in diameter caused by infiltration of inflammatory or cells that are abnormally uncontrollably growing (neoplastic cells).

Picture of Canine Neoplasia called a Histiocytoma

Picture of Dog Lumps on Skin

Warts - Firm bumps that are seen in young and old dogs. Young dogs get warts from a viral infection that are seen around the mouth. Warts in younger dogs go away by themselves.

Pimples/blackheads - Similar to people, dog skin can have the same types of problems. Like humans, you can rid your dog of pimples through cleaning clogged pores and the use of benzoyl peroxicde. Another name for pimple is papule which is defined as a small solid rounded bump rising from the skin that is usually less than 1 centimeter in diameter (less than 3/8 inch across). Papules may open when scratched and become crusty and infected. Dermatologists (and other physicians) call any small solid circumscribed bump in the skin a papule, as opposed to a vesicle which contains fluid or a macule which is flat and even with the surrounding skin.

Photo of Dog Lumps On Skin Pimple (Papule)

Dog Lump on Skin Photo Pimple

Haematoma � a cavity in the skin filled with blood. Haematomas are usually caused by trauma or injury.

Sebaceous cysts - These lumps are caused by an oil producing gland called the sebaceous gland. If the gland gets blocked it gets enlarged as small as a pen eraser and as big as 2 inches wide. If the cyst opens you will see a white pastey substance come out. These cysts can be removed with surgery and can refill if punctured.

Picture of Sebaceous Cyst

Picture of Dog Lump on Skin

Elbow Calluses - Large dogs can get lumps and bumps where their body comes in constant contact with the ground. These lumps are usually calluses or hardened skin. These can be treated by applying petroleum jelly, lanolin or other dog safe softening products.

Hives - Hives are often a reaction to something in your dog's environment. Allergic reactions to bug bites or a medication can cause the skin to swell from 1/2 inch to 2 inches. You could try Benadryl in the dosage 1 mg per pound of body weight. If ineffective, see your veterinarian. Another name for hives are Wheals which tend to look like a circumscribed, circular, raised area of skin caused by swelling due to the retention of fluids in the skin tissues (oedema). Wheals are seen at the site of positive skin test reactions when dogs are allergy tested.

Keeping Track of Dog Lumps on Skin

Janet Tobiassen Crosby, DVM in Your Guide to Veterinary Medicine have some excellent advice for keeping track of dog lumps on the skin. She recommends the following approach:

1. Take a piece of wax paper and a felt marker.
2. Lay the wax paper over the lump. [il]Trace the outer edges of the lump.
3. Date the wax paper.
4. Repeat monthly (or shorter intervals, if your vet suggests) to monitor.

Diagnosis of Dog Lumps on the Skin

Your Veterinarian will look at the physical characteristics of dog lumps on the skin to determine a preliminary diagnosis. They will look at the location, duration, firmness, and size of the canine skin lump or bump.

To be sure of a diagnosis of dog lumps on the skin the veterinarian will take a sample by using a needle to remove some of lump for study in a laboratory (fine needle aspirate).

Treatment of Dog Lumps on Skin

For Lipoma, your Veterinarian will probably watch and wait to see if the dog lumps on the skin shrink or stop growing. If the lump interferes with your dog's quality of life or is growing, then surgery is used to remove the lump.

Warts in younger dogs will go away by themselves. In older dogs they will need to be removed with surgery if they are causing any kind of problem (bleeding, irritation).

If the lump or bump is malignant, then routine cancer therapy including surgery, radiation and chemotherapy are used. It can be difficult to determine the best treatment option.

Sources

Sarah Probst
Information Specialist
University of Illinois
College of Veterinary Medicine

Recent Advances in Mast Cell Tumors
K.A. Selting
College of Veterinary Medicine, University of Missouri, Columbia, MO, USA.

Brevitz, Betsy DVM
Hound Health Handbook

Understanding the Language of the Skin
Peter Hill, BVSc, PhD, DVD, DipACVD, MRCVS
The Royal (Dick) School of Veterinary Studies
The University of Edinburgh, Scotland

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