A breast infection (mastitis) is rare, except around the time of childbirth (see Breast Infection) or after an injury or surgery. Having diabetes or taking corticosteroids by mouth increases the risk of mastitis.
The most common symptom of mastitis is a swollen, red area that feels warm and tender. An uncommon type of breast cancer called inflammatory breast cancer can cause similar symptoms.
A breast infection is treated with antibiotics.
A breast abscess, which is even rarer, is a collection of pus in the breast. An abscess may develop if a breast infection is not treated.
Doctors usually drain (aspirate) an abscess with a needle. Ultrasonography is used to guide placement of the needle. Sometimes doctors need to make an incision to drain the abscess.