A guide to lumps and bumps on cats

You’ve just noticed a lump on your cat – should you be concerned?

Skin lumps in cats are reasonably common, and can have a variety of causes including trauma, bacterial infection, parasites, or tumour growth. If you notice an unusual bump on your feline friend, it’s best to have it promptly assessed by your veterinarian. Early treatment of problematic skin lesions will minimise your cat’s discomfort and, in some cases, could even save their life!

Read on to learn more about some of the most common types of skin lumps on cats, including what to look for and how your vet can help.

Common causes of lumps and bumps in cats

With a variety of underlying causes, lumps can vary in appearance and might be associated with general unwellness symptoms. Some of the most common lump presentations in cats include:

• Allergic: Allergic reactions affecting the skin in cats commonly present as miliary dermatitis , seen as small, red, scabby lumps that the cat will often scratch or lick at. Flea bites are the most common trigger, but pets can also develop allergies to environmental particles such as pollen, or certain foods, plants or chemicals.
• Infection: Cat fight wounds can lead to bacterial infection, swelling, and the development of an abscess (a pocket of pus beneath the skin, which may later burst and release discharge). Cats will usually show signs of pain and lethargy.
• Ticks: These parasites appear as a discrete cream, brown or grey lump on the skin surface, and may range in size from a few mm to a centimetre. Paralysis ticks inject a toxin that can cause potentially fatal tick paralysis.
• Trauma: Crushing injuries such as dog bites can cause soft lumps beneath the skin due to the creation of a:
  • Haematoma: A pocket of blood beneath the skin, or
  • Hernia: A weakening in the body wall, allowing the bulging of internal organs.

Depending on how severe the trauma is, the cat may also show general weakness as well as pain.

• Tumours: Tumours can develop on or beneath the skin, will vary in their appearance, and can range in behaviour from benign (relatively harmless) to malignant (cancerous).

Identifying Benign vs. Malignant Tumours

Benign tumours are non-cancerous, so generally don’t cause issues unless they become irritated or grow large enough to press on vital structures.

Malignant tumours are cancerous, so will either invade into surrounding tissues or spread elsewhere in the body and cause illness.

While the tumours of each class are more likely to have certain characteristics (e.g. benign masses are more likely to have defined borders while malignant masses are more likely to be invasive into surrounding tissues), most tumours cannot be diagnosed on appearance or feel alone. In order to properly confirm a diagnosis, tumour cells need to be sampled and assessed under a microscope.

When to see your vet

If you notice a new lump on your fur-bestie, it’s always a good idea to consult your vet to see if it’s anything to be concerned about. However, advice should be sought more promptly if your cat’s lump:

• Appears to be growing or spreading
• Is painful to touch
• Is ulcerated or oozing
• Is associated with any other signs of unwellness

It’s important to seek urgent veterinary care if you suspect that your cat might have a paralysis tick, as tick paralysis can be fatal for our four-legged friends.

Diagnostic procedures

To get more information about a lump on your pet, your vet may want to perform a test known as fine needle aspirate cytology. This involves using a needle to collect cells from the lump to examine under the microscope. In some cases, your vet will be able to do this during a consultation, but other samples may have to be sent away to a lab for a specialist pathologist vet to examine.

Fine needle aspiration doesn’t always collect enough cells to allow a diagnosis. In these cases, your vet may go on to suggest a biopsy of your pet’s lump, which is a surgical procedure performed under anaesthetic.

If your pet’s mass is suspected to be a malignant tumour, your vet may also discuss imaging tests such as x-ray or ultrasound, so they can check for any visible spread of the tumour.

Treatment options

Lumps secondary to allergic reactions will often require a course of steroids and/or antihistamines to settle the inflammation.

Abscesses in cats commonly require surgery to drain and flush them out. Your cat will then be sent home with pain relief and potentially antibiotics too.

Ticks should be immediately removed with a tick-removing device, and your vet consulted to see if any further treatment is required for your cat.

If your cat has a significant traumatic injury such as a hernia, they will usually require imaging (such as x-rays or ultrasound) to determine the extent of their injuries, followed by surgical repair under anaesthesia.

If your cat’s lump is determined to be a tumour, your vet will make treatment recommendations based on the likely behaviour of the tumour – these range from simple monitoring of benign masses to surgical removal of malignant tumours, with or without further specialist oncology (cancer) treatments.

Home care and monitoring

If your cat is sent home with medication, ensure you follow your vet’s instructions closely for the best and safest result for your pet. If you’re having trouble administering them, ask your veterinary team for help.

After any surgery, your cat will usually need to be kept confined indoors for at least 7-10 days, as allowing them to zoom about too soon may result in post-operative complications, such as the wound re-opening – ouch!

If you have any concerns about the healing of your pet’s treated lump (or lump removal site), such as the development of any redness, swelling or discharge, consult your vet.

Prevention and regular check-ups

You can minimise your feline friend’s chances of getting injured or bitten by keeping them safely indoors or confined to a cat-proof yard or ‘catio’ enclosure. Additionally, ensuring their flea and tick prevention is always kept up to date will help prevent parasitic skin issues and dangerous tick paralysis.

Otherwise, in addition to your feline friend’s annual health assessment, it’s a good idea to check them all over for any new lumps during regular grooming sessions. If you do notice any issues, consult your vet.

With good preventative care and vigilance on your part, and thorough assessments by your vet, any new lumps on your cat are more likely to become just ‘little bumps in the road!’.