Pets of any age can develop lumps and bumps on or under the skin; however, they are more common in older pets and the older they get, the higher their chance of developing a malignant (cancerous) lump.

Next time you’re giving your furry friend a belly scratch or brushing their coat pay attention to what’s on their skin. There are many common types of lumps and bumps found in pets and, although there isn’t always cause for concern, it’s important to have your vet examine your pet when you find one.

Here are some common lumps and bumps to look out for:


Caused by the papillomavirus, warts on dogs and cats are common in older age and are mostly harmless – they can appear as skin tags or small lumps. These warts commonly appear on the head and face of the dog or cat and can be treated depending on their severity and whether it’s irritating your pet. Your vet can do a biopsy of the lump to determine whether it’s a wart or something else and decide on whether to treat the wart – with medication or surgery – or allow it to go away over time.


An abscess is caused by a build-up of pus under the skin, generally because of an infection – perhaps from an animal bite. Your vet can perform a small procedure to drain out the pus and clean the wound with an antibacterial solution. In some cases they may prescribe antibiotics.

Fatty tumours or lipomas

These tumours are more commonly found in older dogs – and especially in pets that are overweight. Also known as lipomas, these tumours are often non-cancerous lumps and can be diagnosed by your vet. This can be done with minimal fuss for your pet – they don’t need to be sedated – via a type of biopsy where the vet takes a sample of the tumour using a thin needle.

“Depending on the size and location of the lipoma, your vet may either recommend monitoring or surgically removing the tumour,” says Dr Shalini Sinnan (Veterinarian).

Cancerous lumps

Mast cell tumours are the most common cancerous lump found on dogs of all ages and one of the most common in cats. These tumours can appear as a lump that look like many other non-cancerous (also called benign) tumours, so it’s important to take your furry friend to the vet for a thorough check.

Melanomas in animals are not caused by the sun and, when found on the skin of the body or head, are more often non-cancerous compared to those found on humans; however, melanoma tumours around the mouth and feet are almost always highly aggressive and will need to be removed as soon as they are noticed. To check for melanomas, when grooming your pet, part the hair and look for dark lumps on the skin.

Breast cancer, also known as mammary carcinomas, is most common in non-desexed female dogs or female dogs that were spayed after two years of age, are rare in male dogs and cats.

Dr Sinnan says, in female dogs, 50% of mammary tumours are benign and 50% are malignant (meaning cancerous). “In contrast, over 85% of mammary tumours in cats are malignant. Surgical removal is recommended for most mammary tumours.”

Unfortunately, all malignant tumours will require surgery as soon as they are noticed, and some may require follow up chemotherapy and/or radiation therapy.

Parasites, such as ticks

In Australia, ticks are common in bushland areas, long grass and on trees and shrubs in your backyard and will attach themselves to a dog or cat that brushes past. A tick is a parasite that will burrow into the skin of your pet to suck its blood. The area where the tick has burrowed in will become inflamed and appear as a lump on the skin of your pet.

If you find a tick on your dog it’s important to remove the entire parasite using tweezers – a slow, even movement will help ensure the head of the tick doesn’t remain buried in your pet’s skin. Where there is one tick there could be more so make sure to do a thorough search all over your pet – focusing on creases and warm, dark places such as under the collar and in their ears. Consult your vet immediately if you notice changes in your pet’s mobility (falling over or unsteady on their feet), vocalisations or breathing and if they start vomiting.

Perianal adenomas

Common in older male dogs who have not been desexed (but also can occur in both desexed male and female dogs), these are lumps that grow from the oil glands near the anus. Sometimes these lumps will also occur in glands on the back, vulva/prepuce and close to the tail. More often these show up as small lumps, but in some cases may develop into large tumours that block the anus and make it difficult for your dog to poo.

Some questions your vet might ask about bumps and lumps on your dog or cat

Visit your trusted vet if you’re concerned about the lump or bump you’ve found on your fur-baby. Some things your vet might ask you when assessing your pet are:

  • When did the lump or bump appear?
  • Did it appear suddenly or was it gradual?
  • Has the shape, colour or size changed?
  • Is your pet exhibiting any other symptoms such as loss of appetite, change in energy level, change in mobility and pain at the site of the lump or bump.