Mastitis is a painful condition of the breast that usually develops when a woman is breastfeeding.

Although women who develop mastitis are often tempted to stop breastfeeding, they should actually be encouraged to breastfeed more frequently. The accumulation of milk in the breast, referred to as milk stasis, is often the initiating factor for this condition and frequent and effective removal of milk from the breast is therefore the most effective management approach.

Milk stasis occurs because the milk is incompletely drained from the breast, usually due to poor mouth-to-breast attachment or due to missed or infrequent feeding sessions. This can lead to pressure being placed on the ducts, which causes milk to leak into the surrounding breast tissue.

Women should continue to breastfeed with the affected breast, but if pain prohibits feeding, the unaffected breast can be used until the other breast becomes more comfortable to use. Ensuring that the baby is well positioned for proper mouth to breast attachment will help to drain the breast milk properly. Applying an edible lubricant to the breast first may also be helpful. Massage should be performed moving from the blocked area towards the direction of the nipple. Once the feeding session is finished, a pump may be used to fully express any remaining milk.

Mothers must be made aware that stopping breast feeding due to mastitis may exacerbate the condition and increase the risk of abscess formation and other complications. Breastfeeding while a mother has mastitis will not harm the baby, even if infection is present (infective mastitis).

If the blocked milk ducts that occur in milk stasis become infected with bacteria, a woman is at risk of forming a breast abscess, which is a severe complication. The abscess can become very painful and may eventually require surgical drainage. Aside from pain, the abscess can also cause the breast to become red, hot and swollen. In addition, a fever may develop.

If not treated promptly, a breast abscess can become a serious problem. Estimates suggest that around 1 in 10 women who develop an abscess are permanently disabled from using the affected breast to feed their baby in the future.

Women who develop mastitis are at an increased risk of developing the condition after future pregnancies. Recurrence of the condition is particularly likely in cases where diagnosis and treatment of the condition was delayed or inadequate.

Some studies suggest that the risk for noninflammatory breast cancer is increased within a year of mastitis developing that is not related to pregnancy or breastfeeding. This form of mastitis is referred to as nonpuerperal mastitis. In cases of this condition, special follow-up care is recommended to carefully monitor patients using preventative screening techniques.