A breast infection is an infection in the tissue of the breast.
Mastitis; Infection - breast tissue; Breast abscess
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 are:
- Breast enlargement on one side only
- Breast lump
- Breast pain
- Fever and flu-like symptoms, including nausea and vomiting
- Nipple discharge (may contain pus)
- Nipple sensation changes
- Swelling, tenderness, redness, and warmth in breast tissue
- Tender or enlarged lymph nodes in armpit on the same side
Exams and Tests
An exam is needed to make the diagnosis and rule out complications such as an swollen, pus-filled lump (abscess). Sometimes an ultrasound is needed to check for an abscess.
For infections that keep returning, milk from the nipple may be cultured. In women who are not breastfeeding, tests may include:
- Breast biopsy
- Breast MRI
- Breast ultrasound
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.
Antibiotic medicines are usually 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.
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.
When to Contact a Medical Professional
Call your health care 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
Grobmyer SR, Massoll N, Copeland EM III. Clinical management of mastitis and breast abscess and idiopathic granulomatous mastitis. In: Bland KI, Copeland EM III, eds. The Breast: Comprehensive Management of Benign and Malignant Disorders. 4th ed. Philadelphia, PA: Elsevier Saunders; 2009:chap 6.
Newton ER. Breast-feeding. In: Gabbe SG, Niebyl JF, Simpson JL, eds. Obstetrics: Normal and Problem Pregnancies. 5th ed. Philadelphia, PA: Elsevier Churchill Livingston; 2007:chap 22.
Spencer JP. Management of mastitis in breastfeeding women. Am Fam Physician. 2008;78:727-31.
Reviewed By: Cynthia D. White, MD, Fellow American College of Obstetricians and Gynecologists, Group Health Cooperative, Bellevue, WA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.