In this condition factsheet:
The Facts on Mastitis
Mastitis, also known as breast infection, is an infection of the breast tissue. It is caused by bacteria that usually enter the breast through small cracks in the nipple, then multiply within the fatty tissue of the breast.
Causes of Mastitis
Mastitis can occur when bacteria commonly found on the skin enter the nipple through small cracks. The bacteria then multiply in the fatty tissue of the breast surrounding the milk ducts (areas of the breast that produce milk), causing swelling, warmth, or pain. The swelling can press on the milk ducts and block them.
Mastitis occurs most commonly in women who are breast-feeding. However, it may occur in women who are not breast-feeding as well. Staphylococcus aureus is the bacterium that is most often associated with this type of infection.
The infection can also occur after milk plugs one of the many milk ducts within the breast, trapping bacteria within the tissue. In this way, a blocked milk duct may also result in a breast infection.
Symptoms and Complications of Mastitis
Women who have mastitis may experience breast pain and may have a fever and feeling of being unwell. The pain is caused by swelling in the breast tissue. Other symptoms include:
- breast tenderness, redness, enlargement, or sensitivity
- warm area in breast tissue
- liquid or pus discharge from nipple
- changes in sensation of the breast
- swollen lymph node on same side as affected breast
- lump in breast
Severe infections may lead to pus-filled cysts called abscesses within the breast tissue. Such cases may require a woman to temporarily stop breast-feeding and may sometimes even require surgery.