Mastitis: when is rest enough, and when do you need a doctor?

Mastitis usually develops within hours: in the morning the breast was just tender, by the afternoon there is a red patch and you feel as though you have flu — chills, aching muscles, fever. It is frightening, especially with a few-week-old baby. The good news is that most cases are manageable, and you do not need to stop breastfeeding. In fact, it is part of what helps.

How to recognise it

• a defined, red, hot, painful area on the breast (usually one side)
• fever above 38 °C, chills
• flu-like exhaustion and aching
• the breast is markedly painful to touch

If there is only a painful lump without fever, that is more likely a blocked duct — I have written about that separately. Mastitis is distinguished by the fever and feeling generally unwell.

The first hours — what to do

• Keep feeding, including from the affected side. The milk is not infectious, and draining the breast is part of recovery. If pain makes that impossible, express just enough for comfort.
• Do not drain as if it were a competition. Aim for normal frequency, not maximum. Over-draining calls up more milk and increases swelling.
• Cool it. A cold compress or gel pack on the sore area, for 15–20 minutes at a time. This is the primary recommendation today.
• Ibuprofen. Safe while breastfeeding, and it treats both pain and inflammatory swelling. Paracetamol for fever.
• Lie down. This is not something to push through on your feet. Ask for help with the baby.
• Drink enough.

What NOT to do

• Do not massage or knead it. The old advice to "push the lump out" is now considered harmful: deep massage further damages and swells inflamed tissue.
• Do not apply prolonged heat. Heat increases swelling. At most, brief warmth before a feed if it helps let-down.
• Do not stop feeding on that side. Stagnant milk is the source of the problem.
• Do not take leftover antibiotics from an old prescription.

When you need a doctor — do not wait

• if your fever and the redness are not improving within 12–24 hours despite rest and drainage
• if your fever goes above 38.5 °C, or you feel very unwell
• if the red area is spreading quickly
• if there is an open wound on the nipple (the most common bacterial entry point)
• if you have had mastitis in the same breast before
• if the area becomes soft and fluctuant, or pus drains — this can indicate an abscess and is urgent

Antibiotics may be needed. Breastfeeding-compatible antibiotics exist — tell your doctor you are breastfeeding and ask them to take that into account. Finish the course, even if you feel better after two days.

Why it happened, and how to prevent it

Behind mastitis there is almost always something that obstructed milk flow: a poor latch, too long a gap, a tight bra or sling strap, sleeping face down, a suddenly changed routine, or a cracked nipple. If we do not find it, it is likely to come back.

That is why it is worth reviewing feeding once you have recovered — not to fix this episode, but to prevent the next one.

How I can help

If you call with a fever, we first go through what to do in the coming hours and whether you need a doctor. Then, once you are better, we look at feeding and find the underlying cause.

This article is for information and does not replace medical assessment. If you have a fever, are getting worse, or see purulent discharge, see a doctor.