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What Is Mastitis?

Mastitis is a condition in which a woman’s breast tissue becomes abnormally swollen or inflamed. It is usually caused by an infection of the breast ducts. It occurs almost exclusively in women who are breastfeeding.

According to the World Health Organization, mastitis can occur with or without the presence of infection (WHO, 2000). As it progresses, mastitis can cause the formation of a breast abscess. This is a localized collection of pus within breast tissue. Severe cases of mastitis can be fatal if left untreated.

Types of Mastitis

Mastitis can occur either with or without infection. If the inflammation occurs without infection, it is usually caused by milk stasis (WHO, 2000). Milk stasis is the buildup of milk within the breast tissue of lactating women.

However, inflammation caused by milk stasis typically progresses to inflammation with infection. This is because the stagnant milk provides an environment in which bacteria can grow.

Mastitis caused by an infection is the most common form.

Sometimes, a break in the skin or nipple can develop. Bacteria (usually Staphylococcus aureus) enter this break and infect the breast tissue (American Cancer Society, 2012). To fight the infection, the body releases a host of chemicals, which cause inflammation.

What Causes Mastitis?

The causes of mastitis include:

  • Bacterial infection: Bacteria are normally found on the skin. Everyone has them, and they are normally harmless. But if bacteria are able to break through the skin, they can cause an infection. If bacteria enter the breast tissue, due to a break in the skin near or around the nipple, they may cause mastitis.
  • Obstruction of a milk duct: Milk ducts carry milk from the breast glands to the nipple. When these ducts are blocked, milk builds up within the breast and causes inflammation and may result in infection.

Who Is at Risk for Mastitis?

The following may increase your risk of developing mastitis:

  • breastfeeding for the first few weeks after childbirth
  • sore or cracked nipples
  • using only one position to breastfeed
  • wearing a tight fitting bra
  • previous episodes of mastitis
  • extreme tiredness or fatigue

In these situations, you are at risk for the buildup of milk within one or both breasts, or at risk for an infection of the breast tissue.

What Are the Symptoms of Mastitis?

The most common symptoms of mastitis are:

  • swelling or breast enlargement
  • redness, swelling, tenderness, or a sensation of warmth on the breast
  • itching over the breast tissue
  • tenderness under your arm
  • a small cut or wound in the nipple or on the skin of the breast
  • fever

How Is Mastitis Diagnosed?

Most cases of mastitis are diagnosed clinically. A doctor will ask you questions about the condition and then give you a physical exam.

The doctor may ask when you first noticed the inflammation and how painful it is. He or she will also ask about other symptoms, whether you are lactating, and whether you are on any medications.

After the physical exam, your doctor will probably be able to tell if you have mastitis. If you have a severe infection, or if the infection does not respond to treatment, then your doctor may ask for a sample of breast milk. The clinic will test the sample to identify the exact bacteria causing the infection. This will allow your physician to give you the best possible medication (Spencer, 2008).

Inflammatory breast cancer can mimic the symptoms of mastitis. If you are being treated for mastitis and the symptoms do not improve, your doctor may test for cancer.

How Is Mastitis Treated?

Treatment for mastitis ranges from the use of antibiotics to undergoing a minor surgical procedure. Some common treatments for mastitis include:

  • Antibiotics: Certain antibiotics can eradicate the bacterial infection causing mastitis. (You should not take any antibiotics that have not been prescribed by your physician.)
  • Ibuprofen: Ibuprofen is an over-the-counter drug that can be used to decrease the pain, fever, and swelling associated with mastitis.
  • Acetaminophen: Acetaminophen can also be used to decrease pain and fever.

Antibiotic treatment usually completely resolves the infection.

Breastfeeding mothers are still able to breastfeed during treatment. The infection is in the breast tissue and not in the milk. Breastfeeding may also help speed the treatment process.

Your doctor may recommend that you undergo a surgical procedure called incision and drainage. During this procedure, the doctor will make a small incision to help drain any abscesses that have formed due to the infection.


The following measures may help prevent mastitis (PubMed Health, 2009):

  • taking care to prevent irritation and cracking of the nipple
  • frequent breastfeeding
  • using a breast pump
  • using a proper breastfeeding technique that allows for good latching by the infant
  • weaning the baby over several weeks, instead of suddenly stopping breastfeeding

Content licensed from:

Written by: Joseph Pritchard
Published on: Sep 05, 2013
Medically reviewed on: Jun 17, 2016: [Ljava.lang.Object;@3a3cd27f

This feature is for informational purposes only and should not be used to replace the care and information received from your health care provider. Please consult a health care professional with any health concerns you may have.
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