Mastitis is painful swelling and redness in the breast. It is especially common among women who are breastfeeding. While it is most common in just one breast it can occur in both.
Mastitis is often caused by trapped breast milk in a milk duct. The trapped breast milk can irritate the tissue around it and cause swelling and pain.
Mastitis can also be caused by a bacterial infection in the breast tissue. Milk ducts or cracked skin around the nipple can allow bacteria to enter the breast and cause an infection.
Mastitis often occurs during breastfeeding but, it is possible to get mastitis at other times. This fact sheet will focus on symptoms and treatment of lactation-associated mastitis.
Factors that may increase your chance of mastitis include:
Mastitis may cause:
Your doctor will ask about your symptoms and medical history. A physical exam will be done. If the diagnosis is uncertain, or if mastitis recurs, your doctor may do a:
In some cases, your doctor may want to look for other conditions that may cause similar symptoms. In these situations, other tests may be performed such as a:
Treatment may include:
Relieving the blockage in the milk duct is an effective way to decrease the pain and swelling. To clear blocked breast ducts try:
To reduce pain and swelling in the breast:
Antibiotics may be used to treat the infection. They may help cure the infection or reduce the risk of more serious but rare complications such as blood infection. If you are breastfeeding, talk to your doctor about which antibiotics are best for you to take so you can continue to breastfeed.
If mastitis does not respond to antibiotics, a localized collection of pus called an abscess might be present. This is usually treated with other antibiotics and a drainage procedure or surgery.
To help reduce your chance of mastitis:
American Congress of Obstetricians and Gynecologists
Office on Women's Health
Women's Health Matters
Amir L. Breastfeeding and Staphylococcus aureus: Three case reports. Breastfeed Rev. 2002;10:15-18.
Barbosa-Cesnik C, Schwartz K, et al. Lactation mastitis. JAMA. 2003;289:1609-1612.
Laibl VR, Sheffield JS, et al. Clinical presentation of community-acquired methicillin-resistant Staphylococcus aureus in pregnancy. Obstet Gynecol. 2005;106:461-465.
Mastitis. American Academy of Family Physicians Family Doctor website. Available at: http://familydoctor.org/familydoctor/en/diseases-conditions/mastitis.html. Updated February 2011. Accessed July 22, 2013.
Masitis. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed. Updated May 1, 2013. Accessed July 22, 2013.
Spencer J. Management of mastitis in breastfeeding women. Am Fam Physician. 2008;78(6):727-731.
11/5/2014 DynaMed's Systematic Literature Surveillance http://www.ebscohost.com/dynamed: Amir L, The Academy of Breastfeeding Medicine Protocol Committee. ABM Clinical Protocol #4: Mastitis, Revised March 2014. Breastfeeding Medicine. 2014;9(5):239-243.
Last reviewed January 2015 by Andrea Chisholm, MD
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.