A breast infection is an infection in the tissue of the breast.
Breast infections are usually caused by a 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.
- 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
Breastfeeding women are usually not tested. However, an exam is often helpful to confirm the diagnosis and rule out complications such as an abscess.
Sometimes for infections that keep returning, milk from the nipple will be cultured. In women who are not breastfeeding, testing may include mammography or breast biopsy.
Infective mastitis is usually treated with a course of an antibiotic. However, a mild case may go without any treatment. If you notice a tender swollen area in a breast when you are breast-feeding, it may be a blocked milk duct or a developing mastitis. It may be reasonable to ‘see how it goes’ over a day or so.
However, if your symptoms become worse you should see a doctor. After talking to you and examining you, they may prescribe an antibiotic. The infection will usually clear within a few days of starting the antibiotic.
Are there any possible complications?
Occasionally, an abscess may form inside an infected section of breast. This is thought to happen in fewer than 1 in 100 cases of mastitis. An abscess is a collection of pus that causes a firm, red, tender lump. The pus can be seen with an ultrasound scan. If the skin over the abscess is not broken, the pus can be drained with a needle and syringe. If the skin is broken (or very thin) it may be better to make a small cut to let the pus drain out.
Some other points about mastitis
- If you are breast-feeding, continue to feed from the affected breast. This helps the milk to continue flowing and stops the breast from becoming engorged and making things worse. After each feed, try to express any remaining milk from the affected breast. Feeding from an infected breast does not harm the baby. If the baby swallows bacteria from an infected breast, the bacteria will be killed by the acid in the baby’s stomach.
- The doctor will choose an antibiotic that is safe to give to breast-feeding women and which will not harm the baby.
- You can take simple painkillers (such as paracetamol or ibuprofen) to ease pain and reduce fever. Cold packs can also be quite soothing when placed on the breast.
- A breast-feeding baby may refuse to feed from the affected breast, as the taste of the milk may change a little. If this occurs, feed from the other breast. Do remember to express the milk (that your baby has refused to take) from the affected breast. This will stop the breast swelling and becoming more painful. It will also keep up the demand for milk, so production does not slow down.
The following may help reduce the risk of breast infections:
- Careful nipple care to prevent irritation and cracking
- Feeding often and pumping milk with a non-traumatic pump to prevent engorgement of the breast
- Proper breastfeeding technique with good latching by the baby
- Weaning slowly, over several weeks, rather than abruptly stopping breastfeeding