Breast Infection (Mastitis)

What is mastitis?

Mastitis is an infection in the breast. This condition is most common in women who are breast-feeding. You may have both general symptoms of illness and breast symptoms including:

  • achy, flulike feeling
  • fever
  • chills
  • headache
  • breast pain
  • breast redness
  • breast firmness
  • nipple or areolar pain
  • difficulty getting milk to flow.

Call your obstetrician or family physician promptly if you have any symptoms of mastitis. The sooner you start treatment, the sooner you will feel better. Prompt treatment may prevent complications, such as a breast abscess (a pocket of pus requiring drainage).

What is the cause?

Breast infections are usually caused by bacteria. Bacteria are normally present on the nipple and in a baby's mouth. They can enter the breast through a cracked nipple or the milk ducts and cause mastitis. The injury may be caused by a baby incorrectly latching on to the breast.

Many factors can make a breast-feeding mother susceptible to mastitis. One of the principal factors is inadequate drainage of milk from your breasts. Poor emptying can occur by allowing too much time to pass between feedings. Also, milk may not drain well if a duct is clogged, or a tight-fitting bra may obstruct milk flow.

Injury to the breast can make a breast-feeding woman more susceptible to mastitis. The injury may be caused by an older baby biting the nipple or kicking the breast. Use of a breast pump that generates excessive vacuum can also injure the breast.

Exhaustion may contribute to mastitis. For example, returning to work, not getting enough sleep, and having house guests may tire a new mother.

What is the treatment?

  • Take all of the antibiotic your doctor prescribes even if you feel much better after a few days. Mastitis is usually treated with an antibiotic for 10 days.
  • Rest and stay in bed as much as possible. Get all the help you can for at least the next day.
  • Drink plenty of fluids, especially if you have a fever.
  • Take medicine for the pain if necessary. You will probably need pain medication during the first 2 days of your illness. Ask your doctor for a prescription if necessary. Ibuprofen is a good choice for over-the-counter pain medication. Only very small amounts of ibuprofen are excreted in breast milk.
  • Nurse more often, especially from the side that is infected, to keep your breasts well emptied.

    You do not have to wean your baby if you have mastitis. In fact, you should nurse more often. You may need to put moist heat on the affected area of your 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 begin feedings on the side that is not infected and then move your baby to the infected breast once your let-down has been triggered.

    If you are pumping milk for a sick or premature hospitalized baby when you develop mastitis, discard the milk collected from the infected side until you are well.

  • Pump your breasts if necessary. If nursing your baby is too painful or doesn't relieve your breast fullness, you may need to rent an electric breast pump. Often an electric pump will comfortably and efficiently empty your breasts.

    You may need to rent a breast pump if:

    • The infected breast is still not emptying 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.

When should I call the doctor?

Call YOUR doctor during office hours if:

  • Your symptoms are not better within 48 hours after you start taking antibiotics.
  • A tender breast lump develops that is not relieved by nursing.

Call your BABY'S doctor during office hours if:

  • You think your milk supply is decreasing.
  • Your baby shows any signs of illness such as fever, poor feeding, tiredness, irritability, trouble breathing, or a rash. Call any time if you are worried.
  • Your baby develops a diaper rash while you are taking antibiotics. The rash may be due to a yeast infection and may require treatment with a medication.
Written by Marianne Neifert, MD, and the clinical staff of The Lactation Program, Rose Medical Center, Denver, CO. 303-377-3016.
Published by McKesson Provider Technologies.
Last modified: 2005-10-24
Last reviewed: 2006-10-04
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.
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