Warning Signs

These signs could indicate the presence of cancer or another disease. If your pet has any of these cancer symptoms, be sure to consult with your veterinarian.

The Veterinary Cancer Society lists ten common signs of cancer.

  • Abnormal swelling that persists or continues to grow
  • Sores that do not heal
  • Weight loss
  • Loss of appetite
  • Bleeding or discharge from any body opening
  • Offensive odor
  • Difficulty eating or swallowing
  • Hesitation to exercise or loss of stamina
  • Persistent lameness or stiffness
  • Difficulty in breathing, urinating, or defecating

About Lumps, Bumps, and Growths

Dogs can sprout a variety of lumps, bumps, and skin growths, especially as they get older. Fortunately, most are merely unsightly or messy rather than harmful. Here is a guide to some typical skin growths in dogs. No growth can be definitively diagnosed by its appearance alone, however, so point out such lumps and bumps to your veterinarian during your dog’s annual physical exam, and be sure to consult your vet if your dog has a lump that grows rapidly, oozes and doesn’t heal, or otherwise bothers you or your dog.


These firm, bumpy growths occur in both young dogs and middle aged to older dogs. “Puppy warts’ are caused by a virus, appear in or around young dog’s mouth, and go away on their own. Older dogs often grow warts on their heads or bodies – but these are not viral in origin, and may not actually be “warts” on biopsy as many are sebaceous adenomas. These should be surgically removed if they routinely bleed or become irritated, or if they grow on the eyelid margin and rub against the eye.

Pimples and black heads

Dogs can get “clogged pores” just like people do, and these may form pimples or blackheads. Facial acne in dogs usually responds well to frequent cleaning with a benzoyl peroxide cleanser. Pimples or blackheads elsewhere can be a symptom of a bacterial skin infection or seborrhea.

Sebaceous cysts

These lumps are oil producing (sebaceous) glands that have become blocked and enlarged, ranging from mosquito-bite-sized to an inch or two in diameter. They contain a whitish, greasy, paste like combination of oil, bacteria, and skin cells. Sebaceous cysts will sometimes open and ooze their contents on their own, or the material can be squeezed out, but usually they will simply fill up again over time. If a sebaceous cyst is particularly messy or in an area where it constantly becomes irritated, it can be surgically removed.


Although these are commonly referred to as “fatty tumors,” they are benign, not malignant. They do not transform to malignant tumors over time. They usually appear in middle-age dogs and older dogs and can range from 1 inch to 8 inches or more in diameter, growing slowly over months to years. If your dog has lipomas, your vet should (1) measure them during your dog’s yearly physical exam and note their location and size on your dog’s medical chart; and (2) when each new lipoma appears and if one enlarges rapidly, do a fine needle aspirate (FNA) of the lump. An FNA takes only a few seconds, can be done during a regular exam, and is virtually painless. The vet inserts a needle into the lump and extracts a drop of its contents to examine under a microscope. If the contents are just fat, you can be reasonably certain the lump is lipoma. If the contents include other types of cells, then the lump may not be lipoma, and it would be prudent to remove it surgically and have it checked by a pathologist. Lipomas that are large enough to make a dog uncomfortable or interfere with mobility should also be removed. Wide margins are not necessary in the removal of lipomas.

Elbow calluses

Large, heavy dogs often develop thick, dark, hairless calluses on the parts of their bodies that contact hard surfaces when they lie down, such as their elbows, hocks, or even over the breast bone. Sometimes these calluses crack and bleed or become infected. They can be treated by providing thickly padded areas for resting, using warm compresses or soaks two or three times a day; applying petroleum jelly, lanolin, vitamin E or another softening and soothing agent (make sure it’s safe to eat if the dog can reach the area and lick it off); and oral antibiotics if the area is infected.

Hives or facial swelling

Hives are warm, firm, rounded swellings that crop up in groups when a dog has been exposed to an allergen, such as a spider bite, bee sting, pollens, or rarely, a medication or vaccine. They can range from about 1/4 inch to 2 inches or more in diameter. Facial swelling-in which the dog’s face becomes puffy is a similar hypersensitivity reaction. If your dog suddenly develops hives, give him or her the antihistamine Benadryl (diphenhydramine) at a dose of 1 mg per pound of body weight (that’s 10 mg for 10 lb dog, 25 mg for 25 lb dog, and so on). If your dog is very itchy or the hives are still spreading one hour later call your vet. If your dog has a swollen or puffy face, call your vet or a vet emergency clinic immediately, because in severe cases the wind pipe may swell shut, leaving the dog unable to breathe and in need of emergency care.

Skin cancer

Dogs can get a variety of skin cancers, including melanomas, mast-cell tumors, and squamous cell carcinomas.  Skin cancer may itch, hurt, or not bother the dog at all. Always point out new skin growths to you vet during your dog’s annual physical exam, and have your vet check out sores that take more then 10 days to heal, lumps that grow rapidly or swell and shrink, or any other skin growth that’s worrisome to you or your dog.

Be sure to consult your vet if your dog has a lump that grows rapidly, oozes and does not heal, or otherwise bothers you or your dog.

This material is provided by experts on dog cancer information from the Veterinary Cancer Society.

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