Mastitis is an inflammation of breast tissue that sometimes involves an infection. It is most common in women who are breastfeeding, but anyone can get it. The inflammation results in breast pain, swelling, warmth, and redness, and may cause flu-like symptoms such as a fever. Mastitis can be caused by milk that is trapped in the breast, a clogged milk duct, or breaks in the skin of the nipple that lead to infection. Treatment for mastitis involves reducing inflammation and pain and preventing an infection from occurring. This may include antibiotics, pain relievers, and continuing to breastfeed or pump milk to help clear the infection. Its important to see a doctor if you have breast symptoms that concern you.