Mastitis

ByJulie S. Moldenhauer, MD, Children's Hospital of Philadelphia
Reviewed/Revised Apr 2024
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Mastitis is painful inflammation of the breast, usually accompanied by infection.

Fever that occurs several weeks after the start of breastfeeding is frequently due to mastitis. Staphylococcal species are the most common causes.

Breast abscesses are very rare and occasionally caused by methicillin-resistant Staphylococcus aureus.

Symptoms and Signs of Mastitis

Mastitis symptoms may include high fever and breast symptoms: erythema, induration, tenderness, pain, swelling, and warmth to the touch. Mastitis is different from the pain and cracking of nipples that frequently accompanies the first days of breastfeeding.

Diagnosis of Mastitis

  • History and physical examination

Diagnosis of mastitis is by history and physical examination. Mastitis must be differentiated from breast engorgement without inflammation or infection.

Treatment of Mastitis

  • Analgesics

  • Complete emptying of breast milk

  • Antistaphylococcal antibiotics

Mastitis that does not respond to conservative measures or manifests as severe (eg, progressive erythema, signs of systemic illness) is treated with antibiotics aimed at Staphylococcus aureus, the most common causative pathogen (1). Examples are

Breast abscesses are diagnosed by ultrasound and are treated mainly with drainage via needle aspiration or surgical incision. Antibiotics aimed at S. aureus are often used.

It is not clear whether antibiotics aimed at methicillin-resistant S. aureus are necessary for treatment of mastitis or breast abscess. In rare situations when there is no abscess and the patient is not improving with antibiotics, milk culture can be done.

Treatment reference

1. Breastfeeding Challenges: ACOG Committee Opinion Summary, Number 820. Obstet Gynecol. 2021 Feb 1;137(2):394-395. doi: 10.1097/AOG.0000000000004254.

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