Breast infections are usually caused by common bacteria (Staphylococcus aureus) found on normal skin. The bacteria enter through a break or crack in the skin, usually on the nipple.

The infection takes place in the fatty tissue of the breast and causes swelling. This swelling pushes on the milk ducts. The result is pain and lumps in the infected breast.

Breast infections usually occur in women who are breastfeeding. Breast infections that are not related to breastfeeding might be a rare form of breast cancer.

Symptoms of a breast infection may include:

• Breast enlargement on one side only
• Breast lump
• Breast pain
• Fever and flu-like symptoms, including nausea and vomiting
• Itching
• Nipple discharge (may contain pus)
• Swelling, tenderness, redness, and warmth in breast tissue
• Tender or enlarged lymph nodes in armpit on the same side

Your health care provider will perform physical exam to rule out complications such as a swollen, pus-filled lump (abscess). Sometimes an ultrasound is done to check for an abscess.

For infections that keep returning, milk from the nipple may be cultured. In women who are not breastfeeding, tests done may include:

• Breast biopsy
• Breast MRI
• Breast ultrasound
• Mammogram 

Self-care may include applying moist heat to the infected breast tissue for 15 to 20 minutes four times a day. You may also need to take pain relievers.

Antibiotics are very effective in treating a breast infection. If you take antibiotics, you must continue to breastfeed or pump to relieve breast swelling from milk production.

In case if the abscess does not go away, needle aspiration under ultrasound guidance is done, along with antibiotics. If this method fails to respond, then incision and drainage is the treatment of choice.

The condition usually clears quickly with antibiotic therapy.

In severe infections, an abscess may develop. Abscesses need to be drained, either as an office procedure or with surgery. Women with abscesses may be told to temporarily stop breastfeeding.

Call your provider if:

• Any portion of your breast tissue becomes reddened, tender, swollen, or hot
• You are breastfeeding and develop a high fever
• The lymph nodes in your armpit become tender or swollen

The following may help reduce the risk of breast infections:

• Careful nipple care to prevent irritation and cracking
• Feeding often and pumping milk to prevent the breast from getting swollen (engorged)
• Proper breastfeeding technique with good latching by the baby
• Weaning slowly, over several weeks, rather than quickly stopping breastfeeding