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Breast Infection (Mastitis)

What is a breast infection?

An infection in the breast is a problem that sometimes happens when you are breast-feeding. The medical term for a breast infection is mastitis.

What is the cause?

Breast infections are usually caused by bacteria. It’s common to have bacteria on the nipple and in a baby's mouth. If a nipple is injured and cracked, the bacteria may get into the milk ducts in the breast and cause an infection.

A number of things can make it easier for the breasts to get infected, such as:

  • Poor drainage of milk from the breasts. This may happen if there is too much time between feedings or you miss feedings. A baby who prefers to feed on one side or does not drink enough milk from the breast can also cause poor drainage of milk. Also, milk may not drain well if a duct is clogged or a bra fits too tightly.
  • Injury to the breast. Nipples can get injured by a baby latching incorrectly onto the breast while nursing, causing a crack or open sore. An older baby may bite the nipple or kick the breast. Use of a breast pump that generates a vacuum that is too strong also can injure the breast.

What are the symptoms?

Symptoms of an infection may include:

  • Achy, flulike feeling
  • Fever or chills
  • Lump in the breast
  • Headache
  • Breast pain, redness, or firmness
  • Trouble getting milk to flow

How is it diagnosed?

Your healthcare practitioner will ask about your symptoms and medical history. Your provider may examine your breast.

How is it treated?

Make sure your baby is feeding well and that you are breast-feeding often. If the baby is not effectively removing the milk, a lactation specialist can help. Also, using a breast pump to keep milk flowing can help.

Your healthcare provider may prescribe antibiotic medicine to treat the infection. The sooner you start treatment, the sooner you will feel better. Prompt treatment may prevent other problems, like a breast abscess (a pocket of pus that will need to be drained).

The infection usually does not pass to the baby. If you are taking an antibiotic, the baby will get some of the medicine through the breast milk. That is usually not a problem for the baby. Talk to your child’s healthcare provider if you have concerns about this.

How can I take care of myself?

  • Follow your healthcare provider's instructions.
  • Take all of the antibiotic your healthcare provider prescribes even if you feel much better after a few days.
  • Rest and stay in bed as much as possible for the first 24 hours. Get all the help you can for at least the next day.
  • Drink plenty of fluids, especially if you have a fever.
  • Eat a healthy diet that includes a variety of fruits and vegetables. Good nutrition helps you fight the infection.
  • Ask your healthcare provider about taking nonprescription pain medicine, like ibuprofen. Nonsteroidal anti-inflammatory medicines (NSAIDs), such as ibuprofen, naproxen, and aspirin, may cause stomach bleeding and other problems. Read the label and take as directed. Unless recommended by your healthcare provider, do not take for more than 10 days for any reason.
  • You don’t have to wean your baby if you have a breast infection. In fact, you should nurse more often, especially from the side that is infected, to keep your breasts well drained. You may need to put moist heat on the affected breast before nursing to help start milk flow. For example, put a warm washcloth on the breast, take a warm shower, or submerge the breast in a warm bath. You can start feedings on the side that is not infected and then move your baby to the infected breast once the let-down of milk has been triggered.

    If you are pumping milk for a sick or premature hospitalized baby when you develop mastitis, your healthcare provider may ask you to discard the milk collected from the infected side until you feel well. Your baby can still drink the milk from the uninfected side.

  • Pump your breasts if necessary. If nursing your baby is too painful or doesn't relieve your breast fullness, you may need to get a hospital-grade breast pump to comfortably and efficiently drain your breasts. You may need to use a hospital-grade breast pump if:
    • The infected breast is still not draining well even though you have followed the treatment suggestions.
    • Nursing your baby from the infected breast is too painful.
    • Your baby refuses to nurse from the infected breast.
  • Ask your provider:
    • How and when you will hear your test results (if a sample of your breast milk was obtained for testing)
    • How long it will take to recover
    • What activities you should avoid and when you can return to your normal activities
    • How to take care of yourself at home
    • What symptoms or problems you should watch for and what to do if you have them
  • Make sure you know when you should come back for a checkup.
Developed by RelayHealth.
Pediatric Advisor 2013.2 published by RelayHealth.
Last modified: 2012-09-17
Last reviewed: 2012-07-08
This content is reviewed periodically and is subject to change as new health information becomes available. The information is intended to inform and educate and is not a replacement for medical evaluation, advice, diagnosis or treatment by a healthcare professional.
© 2013 RelayHealth and/or its affiliates. All rights reserved.
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