Mastitis: Symptoms & Signs

  • Medical Author:
    Melissa Conrad Stöppler, MD

    Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

Medically Reviewed on 5/15/2017

Mastitis is an inflammation of the breast tissue, most often caused by an infection. Mastitis is most common in lactating women. Symptoms include a hard, firm area in the breast that is usually painful. Other symptoms include

Pain while breastfeeding, fever, chills, and generally feeling unwell (malaise or fatigue) can be other symptoms of mastitis. Sometimes, blood or pus can be seen in breast milk when mastitis is present.

Causes of mastitis

Mastitis is usually the result of a bacterial infection. The bacteria typically enter the breast tissue through a cracked nipple that had developed during breastfeeding. Whether skipping breastfeeding or pumping, allowing milk to become trapped in the breast (engorgement) can increase the risk of mastitis.


Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.

Miller, Andrew C. "Mastitis Empiric Therapy." Apr. 10, 2017. <>.

Medically Reviewed by a Doctor on 5/15/2017

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