Women with symptoms of mastitis should see a physician. Breast-feeding with mastitis is generally not harmful to the baby and may actually help speed up recovery. A blocked milk duct Cracked or damaged skin or tissue around the nipple Mastitis most commonly occurs when the breasts are not fully emptied of milk. The milk overflows from the breast glands and engorges the breasts.
Breast engorgement increases the risk of infection.
If bacteria enter the breast through an opening in the nipple or a break in the skin, the breast tissue becomes infected. When bacteria enters the breast ducts, it grows and attracts inflammatory cells. Nasopharyngeal organisms from the infant's mouth, sinuses and other air passages are usually the source of breast infections in breast-feeding women. Breast-feeding with mastitis is usually not harmful to the baby. Improper positioning during breast-feeding, such as leaning over the baby, can lead to mastitis.