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What to Know About Mastitis in Dogs?

Reviewed by Vanessa Farner, DVM on December 08, 2021

Mastitis is a common inflammation of the breast in cattle and other species. It can also affect lactating dogs. 

Although mastitis in dogs is uncommon, you should not rule out the possibility of your dog having this condition as it may have life-threatening consequences if left unchecked.

If you're looking after a nursing dog, it is vital to make yourself aware of mastitis signs, symptoms, and treatment. 

What Is Mastitis in Dogs?

Mastitis is a type of inflammation of the mammary glands in female nursing dogs. Commonly, it is a bacterial infection, but sometimes fungal infections of the breast can also result in mastitis.

Any trauma to the mammary gland can allow the pathogens to cross the skin barrier, entering the mammary gland. In the absence of trauma, living in unsanitary conditions may also cause an infection. In addition, normal nursing of puppies can cause mastitis if suckling puppies scratch the breasts.

The most common pathogens responsible for causing mastitis are Staphylococcus, Escherichia coli, and Streptococcus.

What Causes Mastitis in Dogs?

Besides fungal and bacterial infections, the accumulation of milk in the breast results in mastitis. These cases are commonly linked with the death of a puppy. 

Sudden weaning also results in milk buildup. Inflammation within the mammary gland occurs due to this prolonged period of milk accumulation.

If the nursing dog has a larger puppy litter, the teat canal, a primary physical barrier, remains open for extended periods. This increases the risk of bacteria entering the mammary glands.

What Are the Clinical Signs and Symptoms of Mastitis in Dogs?

Mastitis starts as a mild infection. In the early stages of the disease, it is challenging to detect. One of the ways to detect early mastitis is to pay close attention to the puppies. If the puppies do not gain weight, it indicates the possibility of inflammation of the mammary glands.

The nursing dog becomes reluctant to feed the puppies due to constant discomfort, soreness, and pain. When the puppies do not feed properly, it results in a milk buildup which worsens the inflammation. This is when you begin to notice the following physical symptoms.

  • Slight redness around the nipple
  • Fever
  • Palpable mass 
  • Discolored mammary gland
  • Inflamed teats
  • Loss of appetite
  • Weight loss
  • Lethargy

When the infection persists, your dog may become lethargic. In addition, if the mammary glands become more inflamed and ulcerated, you may notice open wounds or scabs on the breast. The milk may contain pus or blood. Sometimes the milk expressed from the glands has a thick consistency.

When mastitis progresses, the mammary gland turns purple. If you don't treat the condition, it can turn into an abscess. The tissues also start to die from the infection. The infections block the blood supply, causing tissue death. If the infection enters the bloodstream, the nursing dog starts vomiting due to the bacterial toxins. 

What Is the Treatment of Mastitis in Dogs?

Timely treatment of mastitis in dogs will stop the infection from spreading and reduce the damage caused by the infection.

If the infection is mild, early treatment at home will help reduce pain. For example, you can apply warm compresses to the mammary glands. For warm compresses, you can use cabbage leaves or towels.

When your dog lactates, the teats flush out bacteria with the milk. Every six hours, milking out the mammary glands will encourage blood flow and clear the milk ducts. Since accumulated milk worsens the infection, hand milking helps treat the infection. But the frequent expression of milk by hand is too painful for some dogs. In this case, the veterinarian may also prescribe nonsteroidal anti-inflammatory drugs (NSAIDs) for managing pain and inflammation. If your dog does not nurse any puppies, your vet may recommend a medicine to help reduce milk production.

In case of infectious mastitis, vets prescribe antibiotics. Antibiotics such as Clavamox or cephalexin are prescribed. If your vet prescribes these antibiotics, you should look for the side effects in your dog. 

Untreated mastitis can cause gangrene, abscesses, or lead to a septic shock. Therefore, it is vital to treat the condition immediately.   In case of a severe infection, bacteria enter the bloodstream, and this causes sepsis. In this case, immediate hospitalization is vital for your dog to receive IV fluids and antibiotics.

How Do You Prevent Mastitis in Dogs?

You can take some precautions to prevent mastitis in a lactating dog. 

Keep your dog's living area sanitary. Unhygienic conditions put your dog at more risk for bacterial and fungal infections. 

You should also keep the mammary glands clean by giving regular baths to lactating dogs. It‘s also wise to clip puppies' nails so they do not scratch the nursing dog. 

Show Sources

SOURCES:
American Kennel Club: "Mastitis in Nursing Mother Dogs.", "Owner's Guide to Clavamox for Dogs."
FirstVet: "Mastitis in dogs - what you can do to help, and when you should seek advice."
National Institutes of Health: "An Understanding of the Global Status of Major Bacterial Pathogens of Milk Concerning Bovine Mastitis: A Systematic Review and Meta-Analysis (Scientometrics)."
PetMD: "Bacterial Infection of the Breast in Dogs."
VCA Animal Hospital: "Mastitis in Dogs."

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