Mastitis In Cats

Causes, Treatment, and Prevention

mother cat nursing her kittens

Canan Czemmel / Stocksy United

Occasionally, a female cat can develop a very painful infection in one or more of her teats called mastitis, and it is most often seen in female cats that are nursing kittens. You'll usually notice a reddened, swollen teat, and your cat might be lethargic. But sometimes the only sign of mastitis is that the kittens are not growing as quickly as expected.

Left untreated, however, mastitis usually becomes worse, and the cat's teats can eventually become ulcerated. At this point, infection can spread through the animal's bloodstream, a condition called septicemia. This not only endangers the mother cat's life, but it can also put the nursing kittens at risk as they ingest the bacteria-laden milk.

What Is Mastitis?

Inflammation of the breast is called mastitis and can occur in any animal that nurses its young, including humans, dogs, and cats. Inflammation causes redness, pain, and swelling to the affected breast. Mastitis can occur in one or multiple breasts of a cat, but most often affects the teats located closest to the hind legs.

Usually, mastitis in cats is caused by a bacterial infection that makes its way up the milk duct and into the breast tissue. Slight trauma to the nipples caused by vigorously nursing kittens can allow bacteria to enter the female cat's body. Less commonly, a cat that lives in a very unsanitary environment can develop bacterial mastitis even without direct trauma to the teats. Mastitis is not directly contagious to other animals, however.

Mastitis can also occur when too much milk accumulates in the cat's breasts. This can happen when kittens are weaned too quickly, as that doesn't give enough time for milk production to taper off naturally. It can also happen after one or more kittens in a litter die, which abruptly reduces milk consumption.

Symptoms of Mastitis in Cats

An early indicator that your cat has mastitis may be that the kittens it is nursing are not gaining weight as they should. This may be because milk is not able to pass through the inflamed teat canal and therefore the kitten does not get the food it needs. As the mastitis progresses, however, symptoms will appear in the female cat.


  • Swollen breast
  • Red, inflamed teat
  • Purple discoloration of the teat
  • Ulcers or sores on the breast
  • Pus or bloody discharge from the teat
  • Lethargy
  • Fever
  • Loss of appetite
  • Vomiting

You can identify mastitis by looking at your cat's breasts to see if they are swollen, red, and feel warmer than the rest of its body. There may be some discharge from the teat, and the breast will
most likely be painful to your cat if you try to touch it.

Severe cases of mastitis in a cat will cause the breast to turn a purple color, develop sores or ulcerations, and leak blood or pus. These cats often have fevers, are lethargic, have a decreased appetite, and eventually, start vomiting if the infection has entered the bloodstream. At this point, nursing kittens may also become ill as they themselves are infected by the tainted milk.

What Causes Mastitis in Cats?

The most common reason for mastitis to occur is a bacterial infection, although occasionally fungal infections can be to blame. Escherichia coli, Staphylococcus spp., Streptococcus spp., and Enterococcus spp. are the bacteria that most often cause this painful infection.

Bacterial Infection

Usually, female cats that have recently given birth and are nursing are affected by mastitis. Kittens push and climb on the mother cat's breasts while they nurse, and their tiny claws can carry bacteria from feces that then enter the teat through tiny breaks in the skin. Mastitis is even likelier if the cats are living in a dirty environment, such as in a feral colony, a poorly maintained kennel, or a busy animal shelter.

Trauma to Breast

Trauma to a breast can also cause mastitis, even in cats that are not nursing, although this is uncommon. The inflammation caused by some sort of injury can make it easier for bacteria to enter the breast, or simply cause inflammation in the breast without bacterial involvement. Cats that are hit by cars, that have been in fights, or that have endured other trauma to the breast area are all at risk for developing mastitis.

Milk Accumulation

In addition to bacteria and trauma, nursing female cats may develop mastitis if there is sudden milk accumulation in a breast. This can occur due to prematurely weaned kittens, the loss of a kitten, or if kittens are not using all the breasts to nurse.

How Do Vets Diagnose Mastitis in Cats?

Often, your veterinarian will diagnose mastitis simply by observing the appearance of the nursing cat's teats. It's likely, however, that your vet will order tests to rule out other conditions and to confirm the presence of bacteria. Common tests include a complete blood count to determine if the white blood cell count is high; this is an indicator of infection.

Your vet may also examine a few drops of milk under a microscope to check for bacteria or fungi. Occasionally, a sample of the milk will be sent to the lab to be cultured; this means placing the milk sample on a special growth medium and incubating it for a day or two to see if infectious bacteria grow in significant numbers.

How to Treat Mastitis

If mastitis is the result of a bacterial infection, it will need to be treated with antibiotics. Special medicated wipes may be recommended by your veterinarian, and antibiotics, pain medications, and anti-inflammatory medications may also be prescribed to treat the infection and its symptoms.

Your veterinarian might suggest you hand-milk the affected teat every six hours, which reduces swelling and pain. You should keep the cat's bedding and surroundings as clean as possible and clean the affected teat as recommended by the vet.

Cabbage leaf compression, as strange as it may sound, is also regularly recommended to treat mastitis in cats. This is done by taking a cabbage leaf, applying it to the inflamed teat, and leaving it there for about three hours at a time. A bandage or small t-shirt is often used to hold the leaf in place on the cat. The cabbage leaf is then removed for another three hours, and this process is repeated as needed or recommended. This helps to relieve inflammation.

Occasionally, if the mastitis is so severe that it has caused ulcerated tissue or tissue death to the teat, your cat may require surgical removal of the affected tissue.

Prognosis for Cats with Mastitis

If treatment is started promptly, most cats recover completely from mastitis within a few weeks. However, if the infection has spread through the bloodstream, the prognosis is more guarded. That's why it's so important to take your cat to the vet at the first sign of mastitis.

How to Prevent Mastitis

It's not always possible to prevent mastitis, but keeping the bedding and nursing box as clean as possible is the best way to ward off trouble. Mother cats clean themselves and their kittens frequently, but they also lie down to nurse their young, exposing their teats to potential bacterial contamination if the bedding is not clean.

You can also help prevent mastitis by making sure the kittens are nursing from all of the teats and not just a few of them, and routinely checking the teats for normal milk production by gently expressing them.

If you suspect your pet is sick, call your vet immediately. For health-related questions, always consult your veterinarian, as they have examined your pet, know the pet's health history, and can make the best recommendations for your pet.
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