Breast Infection (Mastitis)

Medically Reviewed by Jabeen Begum, MD on September 25, 2023
11 min read

Mastitis is an inflammation of the breast that breastfeeding women can get. It sometimes involves a breast infection, but not always.

The catchall name for inflammation of the breast tissue is mastitis. If you're breastfeeding, it's called lactational or puerperal mastitis. If you're not, it's called periductal mastitis.

Mastitis is most common in women and those assigned female at birth (AFAB), but anyone can get it. Less often it affects men, people who were assigned male at birth (AMAB), and people who aren't breastfeeding.

You might wonder, can you breastfeed with mastitis? Yes. You can safely continue to breastfeed. Nursing might even help to clear up an infection. 

Mastitis breastfeeding isn't a good idea if you have a collection of pus called an abscess. You'll need to have the abscess drained before you continue to breastfeed.

The breast is made of several glands and ducts that lead to the nipple and the surrounding colored area called the areola. The milk-carrying ducts extend from the nipple into the breast tissue under it like the spokes of a wheel. Under the areola are lactiferous ducts. These fill with milk during lactation after you have a baby. When a girl reaches puberty, changing hormones cause the ducts to grow and cause fat deposits in the breast tissue to increase. The glands that produce milk (mammary glands) that are connected to the surface of the breast by the lactiferous ducts may extend to the armpit area.

Mastitis is a common condition in women who breastfeed. As many as 1 in 10 breastfeeding women in the United States get it. The most common cause is when one or more of your milk ducts becomes clogged and the milk inside backs up. This usually happens when you produce more milk than your baby can take in at a time. When milk backs up, it clogs the milk duct and irritates the tissues around it. The clogged milk duct may make your breast swell up or become engorged. 

A blockage can also happen if your baby isn't sucking or attaching properly, or if they favor one breast over the other. Another reason is if you don't feed or pump regularly. Your doctor calls this inflammatory mastitis. A rare type of cancer called inflammatory carcinoma can also cause mastitis.

Mastitis can also happen when bacteria from your baby's mouth or from your skin get into a milk duct through a crack in the nipple. The bacteria can breed in milk that's left in the breast, causing swelling. This is called bacterial mastitis. 

Mastitis is more likely to happen in the first 3 months of breastfeeding. 

Breastfeeding women aren't the only ones who get mastitis. If you're not breastfeeding, bacteria can get into your milk ducts through a cut or crack in the nipple and cause an infection. Mastitis is also more common in women who smoke. Staphylococcus aureus, a common bacteria that lives on your skin, causes many breast infections. 

A subareolar abscess is an infected lump in the areola – the colored area around the nipple. It's not related to breastfeeding. Instead, it happens when ducts in the breasts get plugged up with dead skin cells and debris. Subareolar abscesses are more common in people who are obese or who have nipple piercings.


You're more likely to get mastitis if you:

  • Had mastitis before
  • Have sore or cracked nipples
  • Use the wrong breastfeeding technique
  • Have too much breast milk
  • Put pressure on your breasts (wearing a tight bra, carrying a heavy crossbody bag, wearing a snug seat belt)
  • Are very tired or stressed
  • Smoke
  • Don't pump or nurse on a regular schedule 
  • Don't get proper nutrition
  • Have a chronic health condition such as diabetes 
  • Have an impaired immune system, including from an HIV-positive status

When you have too much milk, you may feel that you need to nurse or pump more often to get it all out of your breasts. But this will cause your body to make even more milk and may make the problem worse. Staying on a regular schedule will help your body adjust to making the right amount of milk for your baby.

The early signs of mastitis can come on very suddenly. You may feel like you're getting the flu before you feel any pain or swelling in your breast. If you feel pain or see redness, call your doctor as soon as possible.

These are some common mastitis symptoms:

  • Breast pain, warmth, and swelling 
  • Redness in a triangle- or wedge-shaped pattern
  • A lump or thickening in the breast
  • A fever of 101 F or higher
  • Flu-like symptoms such as body aches or chills
  • Tiredness
  • Swollen or tender lymph nodes in the armpit on the same side as the affected breast
  • Itching
  • Abscess: A breast abscess can be a complication of mastitis. Noncancerous masses such as abscesses are more often tender and frequently feel mobile beneath the skin. The edge of the mass is usually regular and well-defined. This may be a more serious infection if you have:
    • A tender lump in the breast that does not get smaller after breastfeeding a newborn (If the abscess is deep in the breast, you may not be able to feel it.)
    • Pus draining from the nipple
    • A persistent fever and no improvement of symptoms within 48-72 hours of treatment

A breast infection caused by inflammatory breast cancer also causes redness and swelling. The skin of the breast can look pink, reddish-purple, or like a bruise. You might see dimpling of the skin that looks like the texture of an orange peel. Let your health care provider know about these symptoms right away.

Call your health care provider as soon as you feel any suspicious lump, whether you are breastfeeding or not. Call for an appointment if:

  • You have any abnormal discharge from your nipples.
  • Breast pain is making it difficult for you to function each day.
  • You have prolonged, unexplained breast pain.
  • You have any other symptoms such as redness, swelling, pain that interferes with breastfeeding, or a mass or tender lump in the breast that does not disappear after breastfeeding.
  • If you are breastfeeding, call your doctor if you have any symptoms of breast infection so that treatment may be started right away.

You may need to be evaluated in a hospital's emergency department if the breast pain is linked to other signs of an infection (such as a fever, swelling, or redness to the breast) and if your health care provider cannot see you right away. The below symptoms require emergency treatment:

  • A persistent high fever greater than 101.5 F
  • Nausea or vomiting that is preventing you from taking the antibiotics as prescribed
  • Pus draining from the breast
  • Red streaks extending toward your arm or chest
  • Dizziness, fainting, or confusion

The diagnosis of mastitis and a breast abscess can usually be made based on a physical exam.

  • If it is unclear whether a mass is due to a fluid-filled abscess or to a solid mass such as a tumor, a test such as an ultrasound may be done. An ultrasound may also help tell whether you have simple mastitis and an abscess, or it may help diagnose an abscess deep in the breast. This noninvasive test allows your doctor to directly visualize the abscess by placing an ultrasound probe over your breast. If an abscess is confirmed, aspiration or surgical drainage, and IV antibiotics, are often required.
  • Cultures may be taken, either of breast milk or of material taken out of an abscess through a syringe, to find out the type of organism causing the infection. This information can help your doctor decide what kind of antibiotic to use.
  • Non-breastfeeding women with mastitis, or those who do not respond to treatment, may have a mammogram or breast biopsy. This is a precaution because a rare type of breast cancer can produce symptoms of mastitis.

Mastitis treatment depends on whether you have an abscess. Your health care provider will most likely prescribe antibiotics for a simple infection without an abscess. If you have an abscess, you may need surgery to drain it.

Medications for Mastitis 

Antibiotics for mastitis are safe to use while you breastfeed and won't harm your baby. You should start to feel better 2 to 3 days after you start antibiotics. 

If the infection gets worse or you have a deep abscess that needs surgery, you may need to get IV antibiotics in a hospital.

For simple mastitis without an abscess, your doctor will prescribe oral antibiotics. The most common ones are cephalexin (Keflex) and dicloxacillin (Dycill), but others are available. The antibiotic you'll get will depend on your specific situation, your doctor’s preference, and any drug allergies you may have. If you are prescribed antibiotics, it's important to finish the prescription even if you feel better in a few days. 

Chronic mastitis in non-breastfeeding women can be complicated. The mastitis may come back after treatment. Sometimes, antibiotics don't work well for this type of infection and the mastitis comes back. 

Surgery for Mastitis

Doctors treat abscesses with a minor procedure. This may be done in the doctor's office or in a hospital. First, you will get a local anesthetic to numb the area. The doctor can drain an abscess that's near the surface of your skin with a needle and syringe or through a small cut in the skin. 

If the abscess is deep in your breast, you may need surgery in an operating room to drain it. The procedure is usually done while you are asleep under general anesthesia.

What Happens if You Don't Treat a Breast Infection? 

Can mastitis go away on its own? Sometimes, breast infections do clear up without treatment. But the risk of not treating a breast infection is that pus could collect in your breast and form an abscess. An abscess will usually need surgery to drain.

After you see a doctor, try the following to help your breast infection heal.

  • Pain medication. Take acetaminophen or ibuprofen for pain. These drugs are safe while breastfeeding and will not harm your baby. Your doctor may prescribe a prescription-strength pain reliever if your pain is severe and not relieved with over-the-counter medication.
  • Don't overfeed. You can still breastfeed, but don't nurse more often than usual to relieve the pressure in your breast. If you feed your baby or pump too much, it could stimulate more milk production and make mastitis worse.
  • Apply ice. Place an ice pack or a bag of frozen vegetables on the swollen breast to bring down swelling. Avoid using ice packs just before breastfeeding because it can slow down milk flow.
  • Try lymphatic drainage. Press on your breast as if you were petting a cat, moving your hand from your breast toward the lymph nodes in your collarbone and armpit. This motion gently pushes fluid into your lymph drainage system. 
  • Use reverse pressure softening. Place two fingertips around the base of your nipple. Then pull your fingers away from your nipples while you apply pressure to your breast. This moves fluid away from your areola and reduces pressure.
  • Buy the right bra. Look for one that supports your breasts but isn't too tight.
  • Drink extra fluids. Try to take in about 16 cups a day from foods and drinks like water. Dehydration can decrease your milk supply and make you feel worse.

You might also try these breastfeeding tips:

  • Breastfeed on the side with mastitis first to relieve some of the pressure.
  • Make sure your baby drains the affected breast completely. If the breast isn't fully draining, apply warm, moist heat before you nurse or use a pump to drain it.
  • Massage the breast while you breastfeed. Rub down from the affected area toward the nipple.

If you have a breast infection, you may be seen for a recheck in 24-48 hours.

  • Take all antibiotics as prescribed.
  • Take your temperature three times a day for the first 48 hours after treatment begins. Watch for a fever.
  • Call your doctor if you have a high fever, vomiting, or increasing redness, swelling, or pain in the breast.
  • Follow up with your doctor in 1 to 2 weeks to make sure the infection has gone away. If the infection spreads or an abscess develops, you may need IV antibiotics or surgery.

Mastitis does not cause cancer, but cancer can mimic mastitis in appearance. If a breast infection is slow to go away, your health care provider may recommend a mammogram or other tests to rule out cancer.

Sometimes mastitis is hard to prevent. Some people are more likely to get it than others, especially those who breastfeed for the first time. 

If you're wondering how to avoid mastitis, try these habits:

  • Breastfeed equally from both breasts.
  • Empty your breasts completely to prevent engorgement and blocked ducts.
  • Use good breastfeeding techniques so you don't get sore, cracked nipples. A lactation consultant can help if you need support.
  • Let sore or cracked nipples air dry.
  • Prevent moisture buildup in breast pads or bras.
  • Drink plenty of fluids to avoid dehydration.
  • Eat a well-balanced diet. Get more lecithin from foods like soybeans, peanuts, and egg yolks. Lecithin makes breast milk less sticky to prevent it from plugging up the breast ducts.
  • Practice good hygiene when you breastfeed. Wash your hands and clean your nipples each time.
  • Keep your clothes light and loose. Tight bras put pressure on your breasts.

When treated promptly, most breast infections go away quickly and without serious complications. 

Unless your doctor says otherwise, you can and should continue to breastfeed even when you have mastitis. With proper treatment, symptoms should begin to clear up in 1 to 2 days.

If you have a breast abscess, it may require surgical drainage, IV antibiotics, and a short hospital stay. A small cut is made and usually heals quite well. The outlook for a complete recovery is also good.

If you've been through menopause and have an abscess, it's likely to come back after simple drainage. You'll need to follow up with a surgeon for more treatment. A chronic infection can happen if an abscess is not completely drained. This can cause a change in how your breasts look.

What does an infection in your breast feel like?

A breast infection causes warmth, swelling, and pain in the affected breast. Symptoms can feel like the flu, with a fever, aches, and chills. Other symptoms are a wedge-shaped area of redness and a lump or thickening in the breast.

What kind of breast infections can you get?

Mastitis is a general term for inflammation of the breast tissue that may be caused by an infection. It's called lactational or puerperal mastitis during breastfeeding, or periductal mastitis in people who aren't breastfeeding.

How do you treat a breast tissue infection?

Mastitis treatment often involves antibiotics for an infection. An abscess may need to be drained in a doctor's office or hospital. For pain, take a medicine like acetaminophen or ibuprofen. You can also ice the affected breast. Massaging your breast can help the milk drain from the ducts.

What happens if you don't treat a breast infection?

If you don't treat a breast infection, pus could collect in your breast and form an abscess. An abscess will usually need surgery to drain.