It is always stressful to find a lump on your cat, but there are many possible causes. Sadly, the more common ones are infections and tumours, and veterinary treatment will usually be required.

Lumps can happen due to infection, inflammation, an abnormal growth, fluid build-up, or an anatomical problem like a hernia. You can check a list of some common causes and read a brief explanation below.

What to do

What to do if you find a lump on your cat

If your cat has a bleeding lump, apply gentle pressure to the area for 60 seconds. If the bleeding continues or is severe, continue applying pressure but contact a vet for further advice straight away. Even if the bleeding stops, it is likely to happen again, and a vet assessment is recommended.

If the lump is painful or your cat is unwell, for example, hiding away or refusing to eat, they may have an abscess or injury. Contact a vet for further advice immediately.

If your cat is completely normal apart from the lump, monitor them closely and contact your vet when possible. It can be very useful to take photos of the area where you see or feel the lump. If possible, measuring the lump is also helpful.

Causes

Common causes of lumps in cats

• Infections and abscesses are a common cause of lumps in cats, often caused by fighting with other cats. Usually, these lumps are around the face, lower parts of the legs, lower back or near the base of the tail. There may be a scab in the middle of the lump.
• A small lump is common after an injection, especially after vaccines in kittens. This usually resolves after 3-6 weeks. If it becomes bigger than 2cm, is still growing after a month or is still present after 3 months, testing is recommended.
• Allergic reactions can cause multiple small, scabby lumps all over the cat’s body. They can also cause a small, red lump to develop near the lips or a red raised area on their tummy or back legs.
• Lumps can be due to a tumour or growth. About 50% of growths on a cat’s skin are cancerous, so it is advisable to test any lumps if unsure of their cause. Common examples are squamous cell carcinomas, fibrosarcomas, mast cell tumours, basal cell tumours or warts.
• Cysts related to the sebaceous glands and hair follicles are common. These are not dangerous but can cause irritation and get infected.
• Umbilical hernias can cause a small lump in very young kittens. This is when the space where the umbilical cord was does not close properly. Abdominal fat squeezes through the muscle and can be felt under the skin. Small hernias should close on their own, but larger ones may need surgery.
• Hernias can also happen after a traumatic injury, like a road traffic accident or fall. These require urgent treatment.

When to worry

When should I worry? What do cancerous lumps look like?

If a lump is painful or your cat is unwell, a vet assessment should be done as soon as possible. Joii can help you decide if an emergency vet visit is necessary.

No one can tell if a lump is cancerous just from the way it looks or feels. Testing is recommended, especially if the lump is growing rapidly or surrounded by redness and inflammation.

Prevention

Can I prevent lumps on my cat?

Neutering reduces many of the behaviours that increase the risk of injuries and abscesses, like roaming and fighting.

Reducing sunbathing or using a protective cat sun cream may reduce the risk of a type of skin tumour, especially in white cats.

Diagnosis

What should I look out for if I find a lump on my cat?

If your cat is sleeping more, hiding, or their temperament suddenly changes, they may be in pain.

Changes in appetite or weight loss are very significant.

Some benign growths can turn malignant. If a lump has been present for a while but suddenly changes, this should be checked.

Home treatment

How can I help my cat with their lump?

If a lump starts bleeding, applying gentle pressure for 60 seconds may stop this. If not, seek help from a vet.

Bandages can cause damage to the lump or skin if applied incorrectly. It is usually better to use a recovery collar or a medical vest to prevent injury.

If a lump ruptures and is draining fluid, clean the area thoroughly with saline (roughly 1 tsp salt/500ml cooled boiled water) and seek advice from a vet.

Vet treatment

What is the vet treatment for lumps on cats?

• Pain medication will be prescribed when necessary.
• Abscesses will need to be drained and flushed to remove the infectious material. Antibiotics may also be necessary.
• Suspected allergies may be treated with steroid medications. Further investigations may be advised to determine the trigger for the allergic reaction.
• If a growth or tumour is suspected, one of the two tests below can be performed before deciding if surgical removal is the best treatment:
  • A fine needle aspiration involves scraping a few cells from within the lump with a needle. This is usually a simple test to perform and can provide a lot of information, but the results may be inconclusive.
  • For a definitive diagnosis, a biopsy may be required. This involves removing a portion or the whole of the lump under anaesthesia.

Risk

Is my cat at higher risk of having lumps?

Young male cats more frequently get abscesses and injuries, especially if unneutered.

Older cats are more likely to have a tumour.

White or partially white cats are at higher risk of a type of skin cancer called squamous cell carcinoma, especially if they spend a lot of time sunbathing.

 

Other causes of lumps in cats

Sometimes fluid or blood can build up after surgery or an injury and form a lump under the skin. This is likely to resolve by itself but should be checked by a vet to be safe.