Mastitis is an infection of female breast tissue, which causes pain, inflammation, and redness, sometimes accompanied by fever with chills. It occurs most commonly among women who breastfeed (lactation mastitis), and usually 1 in every 10 breastfeeding women may develop mastitis.

Generally, lactation mastitis develops only in one breast, and the signs and symptoms appear suddenly, which include: redness and swelling on your breast, breast tenderness or feeling of warmth, malaise, breast lump or hard area, pain or a burning sensation that may be continuous or occur only while breastfeeding, white or blood tinged discharge from the nipple, flu-like symptoms such as body aches, chills or fever as high as 101 F (38.3° C) or greater.

Lactation mastitis is often caused by milk stasis or a trapping of milk within the breast. Other causes include: block in the milk duct, bacteria entering your breast, and stagnant milk in a breast. However, the antibacterial properties in your milk help protect your baby against the infection.

Mastitis can be treated with the following measures: antibiotics, over-the-counter painkillers, adjustments to your breastfeeding technique, self-care measures, and avoid wearing tight fitting inner wear.

If you are breastfeeding, you can minimize your risk of developing mastitis by following these measures to stop milk build-up in your breasts: allow your baby to complete feeding on one breast before changing on to the other breast, let your baby feed frequently, especially when your breasts feel full, make sure your baby attaches on to your breasts properly during feeding, do not take your baby off your breast until she finishes feeding, avoid taking a long break between two feeds, and avoid pressure on your breasts from tight fitting clothes.