What causes mastitis?

During breastfeeding, milk that is not moving well can build pressure in part of the breast. A shallow or painful latch, missed feeds, sudden changes in feeding, tight clothing, or pressure on the breast may contribute. The inflammation can cause a tender, firm area, warmth, redness, and flu-like feelings. Infection may develop when bacteria enter through a cracked or sore nipple, but inflammation does not always mean there is an infection.

Mastitis can occur soon after birth or later while breastfeeding. It is not caused by poor hygiene, and continuing gentle milk removal is often part of care unless a clinician advises otherwise.

Rest, drink to thirst, and use a cool pack wrapped in cloth for discomfort. Breastfeed or express milk in a way that feels manageable; avoid forceful massage or trying to empty the breast repeatedly, because this can increase swelling. A lactation specialist can check positioning and latch. A clinician may recommend pain relief or antibiotics when bacterial infection is suspected.

Contact a healthcare professional promptly if you have fever, feel markedly unwell, the red or painful area is spreading, or symptoms are not settling with supportive care. Urgent assessment is needed for severe weakness, confusion, breathing difficulty, or a rapidly worsening breast. A persistent lump may need review to check for an abscess or another cause.

Could this be inflammation, infection, or an abscess? Can someone assess my latch and feeding pattern? Which pain relief is suitable if I am breastfeeding? What changes should prompt a same-day review?