Mastitis is inflammation in the breast caused by milk stasis — when the breast isn't being fully drained, or isn't drained often enough. The single best way to prevent it is responsive feeding on demand rather than to a schedule. It can often be treated without antibiotics, but a fever or flu-like symptoms need urgent medical attention, because mastitis can progress quickly to an abscess or sepsis.
When supporting families with breastfeeding, it's really important to be able to recognise when there are problems and how to resolve them quickly — especially in the case of mastitis. It can be incredibly painful and debilitating for anyone who breast or chestfeeds.
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What mastitis is
Mastitis is inflammation in the breast, caused by milk stasis. This occurs when the breast isn't being fully drained or emptied often enough. It can also be caused by damage to the ducts, which makes it difficult for milk to pass through.
Lighter-skinned breasts will often show a red patch, which may be hot to the touch. This may look different on dark or brown-skinned breasts, where redness may not show easily — so don't rely on redness alone. The breast will feel heavy, may have a lump, and the skin may feel tight.
How you get it
Some of the most common causes are:
- Feeding on a regimented schedule instead of responsively, on demand
- Missing a feed, or going an unexpected length of time between feeds
- Damage to the breast or ducts
- Wearing a bra that is too tight
- Suddenly stopping breastfeeding — going "cold turkey"
How to avoid it
The best way to avoid mastitis is to feed the baby responsively, on demand, rather than to a regimented schedule.
Beyond that: make sure bras fit well, and get measured again if you need to be. And try not to stop breastfeeding, or reduce feeds, suddenly.
How to treat it
Mastitis can often be treated without the use of antibiotics.
Seek urgent medical attention if you develop a fever, lethargy or other flu-like symptoms. Mastitis can turn quickly into sepsis or an abscess.
It's important to keep feeding on the affected breast. You can also try:
- Warm compresses to help milk flow before a feed
- "Dangle feeding" — kneeling over your baby while they lie on their back
- Cold compresses between feeds to reduce inflammation
If symptoms don't improve in 24–48 hours, seek medical advice. If mastitis keeps recurring, it's worth a full feeding assessment to find out why the breast isn't draining properly — position and attachment and tongue-tie are both common underlying causes. You can find an IBCLC through Lactation Consultants of Great Britain.
Common questions
Should you keep breastfeeding with mastitis?
Yes. Continuing to feed on the affected breast helps clear the milk stasis that caused it in the first place.
Does mastitis always need antibiotics?
No — it can often be resolved without them. But a fever, lethargy or flu-like symptoms need urgent medical attention.
What does mastitis look like on darker skin?
The redness that shows on lighter skin may not be visible. Look instead for heat, heaviness, a lump, and tight-feeling skin.
Can a tight bra cause mastitis?
Yes. A bra that is too tight is a recognised cause, because it restricts drainage. Get remeasured if you're unsure of your fit.
About the author
Charlotte Treitl is an International Board Certified Lactation Consultant and a Babyem tutor, supporting families with infant feeding and teaching practitioners how to recognise and resolve feeding problems early.
Learn to spot feeding problems early
Babyem's accredited training teaches practitioners how to assess feeding, recognise problems like mastitis and tongue-tie, and refer confidently.