What are signs of mastitis while breastfeeding?
A hot, tender or swollen area with flu like symptoms can be a sign of mastitis. Seek advice if symptoms worsen or don’t improve.
The short answer
Mastitis can cause a hot, tender or swollen area in the breast, pain and flu like symptoms. NHS guidance says to contact a GP or NHS 111 if symptoms get worse or aren’t improving within 12 to 24 hours.
Symptoms can come on quickly
The NHS says mastitis usually affects one breast and symptoms often appear quickly. Signs can include a swollen area that feels hot or painful, a hard area or lump, burning pain, nipple discharge, aches, tiredness, chills or a high temperature.
Redness may be harder to see on darker skin. Pay attention to how the area feels and to other symptoms, and contact a health professional if you’re concerned. Symptoms can have more than one cause, so this page can’t confirm a diagnosis.
Contact a health professional
NHS guidance advises contacting a GP or NHS 111 if symptoms get worse at any time or aren’t improving within 12 to 24 hours. If you feel seriously unwell or think you need urgent help, use your local urgent or emergency service.
A professional can check the symptoms and advise whether treatment is needed. Don’t use an app, a feeding log or this article to decide whether to delay care.
Ask for feeding support too
The NHS advises continuing to breastfeed when your baby wants to feed, unless a doctor tells you otherwise, and getting help with positioning and attachment. If feeding is too painful or your baby can’t feed from the affected breast, ask a professional for advice about expressing.
These are UK NHS recommendations. If you live elsewhere, contact the health service in your area and follow its advice.
Sources and further reading
Sources checked 12 October 2026. This page doesn’t replace advice from your own doctor.