Mastitis, which mainly affects breast-feeding women, causes redness, swelling and pain in one or both breasts. Mastitis is an inflammation of breast tissue that sometimes involves an infection. The inflammation results in breast pain, swelling, warmth and redness. You might also have fever and chills.

Where is mastitis located?

Mastitis is an infection in the tissue of one or both of the mammary glands inside the breasts. It usually affects women who are producing milk and breast-feeding. There is often a hard, sore spot inside the breast.

Where on the breast does mastitis occur?

What causes mastitis? Mastitis occurs when bacteria found on skin or saliva enter breast tissue through a milk duct or crack in the skin. Milk ducts are a part of breast anatomy that carry milk to the nipples. All genders have milk ducts and can get mastitis.