Snapshot A 33-year-old G2P2 woman presents with fever, chills, and acute onset pain of her left breast. She recently had her second child and has been breastfeeding exclusively for about 1 month. She reports having had this type of pain before with her first child. The pain resolved with antibiotics. On physical exam, her left breast is noted to be engorged and tender to palpation. There is localized erythema, induration, and warmth. She is given antibiotics and told to continue breastfeeding. Introduction Clinical definition inflammation of the breast often associated with milk stasis during lactation Epidemiology incidence 3-20% of lactating women demographics occurs in lactating women often occurs within first 12 weeks post-partum risk factors lactation injury to nipple poor attachment of infant to breast history of prior mastitis Pathophysiology pathophysiology milk stasis also creates favorable conditions for growth of bacteria infection often starts from nipple fissures often due to Staphylococcus aureus Prognosis prognostic variable favorable appropriate antibiotic treatment survival with treatment very good Presentation Symptoms primary symptoms tender, hot, and swollen breast usually unilateral flu-like myalgia chills fever Physical exam inspection localized redness on the breast often wedge-shaped warmth and induration on the breast cracked nipples or visible fissure swollen lump may indicate breast abscess may have purulent nipple discharge Imaging Ultrasound indication If breast abscess is suspected finding fluid pocket seen inside breast Studies Labs may see elevated white blood cell count Diagnostic criteria mastitis is typically diagnosed clinically based on physical exam Differential Engorgement pain relief and resolution of symptoms with emptying of milk Fibroadenoma no signs of infection Treatment Conservative continue breastfeeding safe for infants not advisable in women with human immunodeficiency virus (HIV) empty breasts of milk every 6 hours indication for mild symptoms lasting less than 1 day Medical dicloxacillin or cephalexin indications symptoms persist after 1 day of effective, regular milk removal visible nipple fissure breast abscess clindamycin or trimethoprim-sulfamethoxazole indication if MRSA is suspected Operative surgical drainage indication breast abscess is diagnosed techniques first-line needle aspiration with or without ultrasound guidance otherwise incision and drainage for large abscesses Complications Breast abscess 3-12%of women with mastitis develop breast abscess treatment surgical drainage