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Why Are There Lumps Under Your Dog’s Skin?

3 minutes
Why Are There Lumps Under Your Dog’s Skin?
Last update: 07 August, 2022

Perhaps you have come across a lump when you were petting or grooming your pet and the alarm bells go off. However, although an immediate visit to the veterinarian would be smart, you should know that most of the time lumps under your dog’s skin aren’t so serious.

An issue with different causes

There are many possible causes for lumps under your dog’s skin. A professional will be the one to determine its origin and come up with a treatment.

In addition, in this and all cases, the sooner you take your dog to the vet to get diagnosed, the better their chances are at treating the lump. Most likely, the vet will be able to determine the cause upon the first visit. However, they may request cytology and even a biopsy.

Learn about the different types of lumps you may find under your dogs’ skin. In the vast majority of cases, they’re not serious. However, in case there is one, you can make an appointment with your vet right away.

Why might there be lumps under your dog’s skin?

Some things that can cause lumps to appear under your dog’s skin are:

  • Vaccinations. After a dog is given a vaccine, a small, hard lump may form in the area that was injected. It will disappear by itself in a few days.
  • Bumps and bruises. If the animal falls or is accidentally hit, a bump may appear with a bruise. This also tends to disappear in a matter of hours.
  • Other injuries. An insect bite or an infected wound may cause an abscess.

Other reasons for lumps

Other than dogs having benign lumps, there are sebaceous cysts and lipomas. In some cases, it’s necessary to perform a simple surgery to remove them.

Papules are another kind of cutaneous injury that dogs can get that causes lumps to form. These are small eruptive tumors caused by allergies, exposure to irritating or toxic substances, or follicular infections.

Also, pay attention to whether the animal has warts. Although they are usually benign, they could become somewhat inconvenient, especially in elderly or immunosuppressed dogs.

Cases in which lumps are dangerous

Some of the lumps that may appear on a dog’s skin can be malignant tumors. This is the case with:

  • Breast Tumors. This is one of the most common forms of cancer in female dogs that have not been spayed.
  • Hemangiosarcoma. One of the possible signs of this is the appearance of lesions on the skin in the form of red or black nodules or the appearance of lumps underneath what appears to be normal skin.
  • Fibrosarcoma. This appears as small bumps around the spine, skull or pelvic region.
  • Squamous cell carcinoma. These usually start as sores that don’t heal or with the presence of small lumps.
  • Mast cell tumors. These can be formed from cells designed to defend the dog’s body from the invasion of germs or foreign objects. These usually look like firm or soft bumps.

As we always say, it’s better to prevent than to treat. So it’s best that you ensure that you periodically check your pet so you can be aware of the appearance of any physical signs or behavior that may indicate an anomaly.


All cited sources were thoroughly reviewed by our team to ensure their quality, reliability, currency, and validity. The bibliography of this article was considered reliable and of academic or scientific accuracy.



This text is provided for informational purposes only and does not replace consultation with a professional. If in doubt, consult your specialist.