Breast infection
Mastitis; Infection - breast tissue; Breast abscess - post partum mastitis; Breastfeeding - mastitis
A breast infection is an infection in the tissue of the breast.
The female breast is composed mainly of fatty tissue interspersed with fibrous or connective tissue. The circular region around the nipple is often a different color or pigmented. This region is called the areola.
Most breast infections occur in breastfeeding women when bacteria enters the breast through cracks in the nipple. In severe infections, abscesses may occur. Antibiotics may be indicated for treatment.
The female breast is either of two mammary glands (organs of milk secretion) on the chest.
Mastitis is inflammation of the breast, most commonly due to infection. Mastitis usually occurs in breastfeeding women if milk ducts are blocked, and milk cannot flow out. Bacteria can enter through a duct opening or a crack in the skin of the nipple, and multiply in the milk. Symptoms of mastitis include breast pain, swelling, warmth, and redness.
Causes
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 inflammation that are not related to breastfeeding might be due to a rare form of breast cancer.
It's normal during the first week after a baby is born for a mother's breast to become heavy, and tender, and full as the milk is coming in. And even before that as the blood flow is expanding and the lymph flow is expanding to allow the milk to come in. But sometimes that progresses to something we call engorgement. I'm Dr. Alan Greene and I want to talk briefly about engorgement. What causes it, how you can prevent it, and what to do if engorgement does happen. We call it engorgement if the pain becomes really severe because the milk is so full in the breasts that it squeezes shut some of the blood and lymph vessels. So causes swelling in the tissues. It's not just too much milk. It's real swelling of the breasts. And it can be quite painful and make nursing kind of difficult. Probably the best way to prevent engorgement is frequent, early feeding. If you feed as often as the baby wants to, and at least every 2 to 3 hours when the baby is awake during the day, and no longer than 4 or 5 hours one stretch at night during that first week will often prevent engorgement. Engorgement is less common, too, if you don't do supplemental feedings. But even if you do everything perfectly, some women will still become engorged. It's not a guarantee. If you do and don't do anything, the engorgement will likely last for 7 to 10 days. But if you take steps to treat the engorgement, usually it will be gone within maybe 24 to 48 hours, at least the worst part of it. So what does treating engorgement mean? It's a couple of very simple steps. The first one is really to try to empty the breasts completely. Again, going back to frequent feeding and to encourage the baby to nurse to finish the first breast first. Don't try to switch breasts in between, but start and let them empty as much as they can. And then only after they come off it their timing, try the other breast. Then start with the opposite one next time. Then you can do a lot with cool and warm compresses. Doing a cool compress in between nursing can help reduce the swelling and reduce the tenderness. And then a warm compress you want to switch to in the 10 to 15 minutes before nursing to help encourage let down and help the breast drain more fully. You can actually get compresses that are made for this purpose that you can warm or you can cool. And they can fit inside a nursing bra. Another thing that can be very helpful are cabbage leaves. There have been a few studies suggesting this and a lot of personal experience people have had just taking a cabbage leaf out of the refrigerator and wearing it as a compress. There seems to something in there that does help. Whatever you do, you may also want some pain relief, something like acetaminophen. And if that's necessary don't hesitate if that's something that's going to keep you nursing because breast milk is the very best thing for kids.
Symptoms
Symptoms of a breast infection may include:
- Breast enlargement or fullness 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, and warmth in breast tissue
- Skin redness, most often in wedge shape
- Tender or enlarged lymph nodes in armpit on the same side
Exams and Tests
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:
Treatment
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.
If there is an abscess that does not go away, needle aspiration under ultrasound guidance is done, along with antibiotics. If this method fails to cure the abscess, then incision and drainage is the treatment of choice.
Outlook (Prognosis)
The condition usually clears quickly with antibiotic therapy.
Possible Complications
In severe infections, an abscess may develop. Abscesses need to be drained, either as an office procedure or with surgery. A wound dressing would be needed to help with healing after the procedure. Women with an abscess may be told to temporarily stop breastfeeding.
When to Contact a Medical Professional
Contact 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
Prevention
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
- Timely treatment of a breast infection before it progresses to a breast abscess
References
Dabbs DJ, Rakha EA. Metaplastic breast carcinoma. In: Dabbs DJ, ed. Breast Pathology. 2nd ed. Philadelphia, PA: Elsevier; 2017:chap 25.
Dabbs DJ, Weidner N. Infections of the breast. In: Dabbs DJ, ed. Breast Pathology. 2nd ed. Philadelphia, PA: Elsevier; 2017:chap 3.
Dinulos JGH. Bacterial infections. In: Dinulos JGH, ed. Habif's Clinical Dermatology. 7th ed. Philadelphia, PA: Elsevier; 2021:chap 9.
Klimberg VS, Hunt KK. Diseases of the breast. In: Townsend CM Jr, Beauchamp RD, Evers BM, Mattox KL, eds. Sabiston Textbook of Surgery. 21st ed. St Louis, MO: Elsevier; 2022:chap 35.
Woods CR. Subcutaneous tissue infections and abscesses. In: Long SS, ed. Principles and Practice of Pediatric Infectious Diseases. 6th ed. Philadelphia, PA: Elsevier; 2023:chap 73.
Version Info
Last reviewed on: 10/10/2022
Reviewed by: Jonas DeMuro, MD, Diplomate of the American Board of Surgery with added Qualifications in Surgical Critical Care, Assistant Professor of Surgery, Renaissance School of Medicine, Stony Brook, NY. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
