Mastitis: Symptoms, Treatment and When to Get Help

Mastitis can come on fast. One evening you notice a sore spot, and by morning your breast is red and hot and you feel like you have the flu. It’s miserable, but it’s also common and very treatable, and in most cases you can keep breastfeeding the whole time.

Treatment advice has changed in recent years. The Academy of Breastfeeding Medicine (ABM) Protocol #36 from 2022 describes mastitis as a spectrum of inflammation, and its recommendations move away from heat, deep massage and pumping “to empty.” Here’s what that means for you.

Mastitis symptoms

Mastitis usually affects one breast. According to the NHS and Cleveland Clinic, common symptoms are:

• A red, hot, swollen area of the breast (redness can be harder to see on brown or black skin)
• A hard, wedge-shaped or lumpy area that hurts
• Burning pain, either constant or during feeds
• Flu-like symptoms: fever, chills, aches and tiredness
• Sometimes nipple discharge, which may be white or streaked with blood

The mastitis spectrum

The ABM describes a range of conditions that can blend into one another:

Stage	What’s happening	Typical picture
Ductal narrowing	Swelling around milk ducts slows milk flow	Tender firm area, you feel well. See clogged milk duct.
Inflammatory mastitis	Inflammation spreads through part of the breast	Red, swollen, painful area, often with fever and aches, even without infection
Bacterial mastitis	Bacteria add an infection to the inflammation	Symptoms persist or worsen despite good home care
Phlegmon	A firm, mass-like area of inflammation	Hard area that doesn’t soften as mastitis improves
Breast abscess	A collection of pus	A painful lump, sometimes with fluid you can feel under the skin; needs drainage

The key point: fever and feeling unwell don’t automatically mean infection. The ABM notes that the body’s inflammatory response alone can cause these symptoms, which is why care starts with reducing inflammation.

What causes mastitis

The most common driver is oversupply: making more milk than your baby needs, which puts pressure on the ducts and surrounding tissue. Cleveland Clinic and the ABM also list:

• Pumping after feeds or pumping “to empty”
• Long gaps between feeds or a sudden change in routine
• A shallow latch or nipple damage
• Pressure from tight bras or clothing
• Deep massage of the breast

Treatment at home

These steps follow ABM Protocol #36, the NHS and Cleveland Clinic.

1. Keep feeding normally. Breastfeed on cue from both sides, as you would on a normal day. Don’t stop suddenly, and don’t add extra feeds or pumping sessions on the sore side. If you pump, express about what your baby takes. If feeding from that side is too painful, hand express just enough to stay comfortable.
2. Rest. Treat this like the flu. Accept help with chores and baby care where you can.
3. Ice. A wrapped ice pack or cold compress reduces pain and swelling. The NHS suggests about 10 minutes at a time, every hour.
4. Anti-inflammatory pain relief. Ibuprofen reduces inflammation and pain; acetaminophen helps pain and fever. Both are considered compatible with breastfeeding. Use the standard adult dose on the label unless your doctor advises otherwise, and ask your doctor or pharmacist if you have other conditions or take other medicines. The NHS advises avoiding aspirin. See our guide to ibuprofen and Tylenol while breastfeeding.
5. Gentle touch only. Avoid deep massage, which the ABM says can worsen inflammation and injure tissue. Very light strokes toward the armpit (lymphatic drainage) may ease swelling.
6. A supportive bra that doesn’t dig in, and avoid sleeping on the affected side.

Heat, long hot soaks and creams or oils on the breast are no longer recommended as treatment, though the ABM acknowledges a little warmth feels comforting to some people.

When antibiotics are needed

Antibiotics treat bacterial mastitis. They don’t help inflammation that isn’t infected, and the ABM notes that unnecessary antibiotics can disrupt the healthy bacteria in the breast.

Your doctor is likely to consider antibiotics if:

• You are not improving 12–24 hours after starting home treatment (NHS)
• Fever, a fast heart rate or other whole-body symptoms continue for more than about 24 hours (ABM)
• You are getting worse or feel very unwell

If you are prescribed antibiotics, take the full course. The NHS advises going back to your doctor if you are not better 48 hours after starting them. Your doctor may also send a sample of your milk to the lab to choose the right antibiotic.

When to seek urgent care

Call your doctor the same day if you have a fever, flu-like symptoms or a breast that is getting redder, more swollen or more painful.

Seek emergency care right away if you have signs of sepsis, a rare but life-threatening reaction to infection. The CDC lists:

• Confusion or disorientation
• A high heart rate or weak pulse
• Shortness of breath
• Fever, shivering or feeling very cold
• Clammy or sweaty skin
• Extreme pain or discomfort

Also seek care promptly if you can’t keep fluids or medicine down, or if you notice a lump that doesn’t soften, a pocket of fluid, or pus. These may point to an abscess, which usually needs to be drained by a doctor with a needle or small procedure. You can usually keep breastfeeding during and after abscess treatment.

Because mastitis can look like other breast conditions, the ABM and Cleveland Clinic advise that redness or swelling that doesn’t clear with treatment, or keeps coming back in the same place, should be evaluated, sometimes with imaging.

Preventing mastitis

• Feed on cue and avoid long, unplanned gaps between feeds.
• Don’t pump after feeds to “empty” the breast unless a lactation consultant has recommended it for a specific reason.
• Get latch help early if feeds hurt or your nipples are damaged. Our guide to sore nipples covers common causes.
• Change gradually. When returning to work, dropping feeds or weaning, reduce slowly over days.
• Address oversupply. If you always feel overfull or leak heavily, a lactation consultant can help you bring supply in line with your baby’s needs.
• Wear comfortable bras without pressure points.

Getting support

Mastitis is exhausting, and it’s normal to wonder whether to keep breastfeeding. With the right care, most people can, and stopping suddenly can make symptoms worse. A lactation consultant can help you find the cause so it doesn’t come back. Find help through our breastfeeding support page, and see our breastfeeding problems hub for related conditions such as engorgement.