A breast abscess is a collection of inflammatory exudate and white blood cells in the breast tissue. It presents as a painful or tender lump in the breast tissue with overlying skin erythema, and it is sometimes associated with fever. A breast abscess can present primarily, without an inciting illness, or secondarily to mastitis or cellulitis of the breast.

The most common microorganism causing this condition is Staphylococcus aureus, with methicillin-resistant S aureus (MRSA) becoming an increasingly important pathogen.

Risk factors for developing a breast abscess include female sex, active breastfeeding, obesity, diabetes mellitus, and tobacco use.

Treatment for this condition includes abscess drainage and antibiotic therapy, with continued breastfeeding or lactation if applicable.