Breast Infection (MASTITIS)

Mastitis is the name for an infection in the breast. The condition occurs in up to 10% of breastfeeding women, most commonly in the early postpartum weeks. Flu-like symptoms – such as chills and fever – typically are present, together with pain and redness in the affected area of the breast.


A breast infection usually is caused by bacteria which normally are present on the nipple and in the baby’s mouth. Many factors can make a nursing mother susceptible to mastitis. One of the most common is not draining the breasts well, usually by going too long without breastfeeding or pumping. Sore nipples also can lead to mastitis when infecting bacteria enter the breast through a cracked nipple. Other predisposing factors include:  a blocked duct; trauma to the breast (i.e. infant teething, incorrect infant latch-on, or over-vigorous use of a pump); maternal exhaustion (returning to work, sleep deprivation, house guests), or wearing a tight-fitting bra.


Mastitis causes general symptoms of illness – such as an achy, “flu-like” feeling, fever and chills, headache or body aches. Noticeable symptoms also are present in the affected breast, including an area of redness, pain and tenderness, firmness, fullness, warmth, and poor milk flow.


1.   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 and the less likely you will develop the complication of a breast abscess (see below).

2.   Mastitis is treated with antibiotics for 10 – 14 days. You should feel much better within 36 to 48 hours. Continue to take the antibiotic your doctor prescribes for the full course, as relapses are common when treatment is discontinued early, or a painful abscess can form.

3.   Rest and stay in bed as much as possible, and drink plenty of fluids, especially if you have a fever. Enlist all the help you can for the next two days.

4.   You will probably require pain medication the first two days of your illness. Ask your doctor for a prescription if necessary. Ibuprofen is a good choice for over-the-counter pain medication, and only minimal amounts appear in your milk.

5.   Nurse more often, especially on the affected side, to keep your breasts well drained. Applying moist heat to the affected area before nursing (i.e., a warm washcloth covered with plastic wrap to maintain the heat longer) can help start milk flow. Cool compresses applied between feedings may help relieve discomfort.

6.   You can begin feedings on the “good” side and then move your baby to the affected breast once your let-down has been triggered. 

7.   If nursing your baby is too painful or doesn’t relieve your breast fullness – or if your baby refuses to nurse on the affected breast – you should use an electric breast pump to comfortably and efficiently empty your breasts until the infection subsides. To find a breast pump rental station near you, contact the hospital where you delivered or call the manufacturers:  Medela (1-800-TELL-YOU) or Ameda (1-866-99-AMEDA).

 Call Your Doctor If:

1.   Your symptoms are not much better within 48 hours after starting antibiotics or you get sicker any time during treatment. You should be re-evaluated by your doctor, who may prescribe a different antibiotic.

2.  A persistent, extremely tender area develops in the affected breast. A serious complication of mastitis is a breast abscess (a walled off pocket of pus) that must be drained. 

3.   You develop sore nipples after taking antibiotics. This could be due to a yeast infection of your nipples, which requires treatment with an antifungal medication. Many women describe the discomfort caused by yeast-infected nipples as burning, shooting, or stabbing pain that radiates from the nipples deep into the breast, both during and after nursing.

Call Your Baby’s Doctor If:

1.   You think your milk supply is decreasing and your baby acts hungry.  Sometimes milk production remains low in the breast with mastitis.

 2.   Your baby shows any signs of illness, including fever, poor feeding, lethargy, irritability, or rash. Your baby may have become infected with the same bacteria that caused your mastitis.

3.   Your baby develops a diaper rash while you are taking antibiotics. The rash may be due to a yeast infection, which will require treatment.

Copyright ©  2011  Marianne Neifert, MD, MTS     May be duplicated if authorship is cited.