Mastitis refers to inflammation of breast tissue, and is a common complication of breastfeeding. It can occur with or without associated infection.

Mastitis can be caused by obstruction in the ducts and accumulation of milk. Regularly expressing breast milk can help prevent this occurring.

Mastitis can also be caused by infection. Bacteria can enter at the nipple and back-track into the ducts, causing infection and inflammation. The most common bacteria is staph aureus.



Mastitis presents with:

  • Breast pain and tenderness (unilateral)
  • Erythema in a focal area of breast tissue
  • Local warmth and inflammation
  • Nipple discharge
  • Fever



Where mastitis is caused by blockage of the ducts, management is conservative, with continued breastfeeding, expressing milk and breast massage. Heat packs, warm showers and simple analgesia can help symptoms.

When conservative management is not effective, or infection is suspect (e.g. the woman is febrile), antibiotics should be started. Flucloxacillin is first line, or erythromycin if allergic to penicillin. A sample of milk can be sent to the lab for culture and sensitivities. Fluconazole may be used for suspected candidal infections.

Women should be encouraged to continue breastfeeding, even when infection is suspected. It will not harm the baby and will help to clear the mastitis by encouraging flow. Where breastfeeding is difficult, or there is milk left after feeding, they can express milk to empty the breast.

A rare complication if not adequately treated, is a breast abscess. This may need surgical incision and drainage.


Candida of the Nipple

Candidal infection of the nipple can occur, often after a course of antibiotics. This can lead to recurrent mastitis, as it causes cracked skin on the nipple that create an entrance for infection. It is associated with oral thrush and candidal nappy rash in the infant.

Candida infection of the nipple may present with:

  • Sore nipples bilaterally, particularly after feeding
  • Nipple tenderness and itching
  • Cracked, flaky or shiny areola
  • Symptoms in the baby, such as white patches in the mouth and on the tongue, or candidal nappy rash


Both the mother and baby need treatment, or it will reoccur. Treatment is with:

  • Topical miconazole 2% after each breastfeed
  • Treatment for the baby (e.g. miconazole gel or nystatin)


Last updated September 2020