Everything you need to know about mastitis: symptoms, causes, and appropriate treatments

You wake up with a painful, hot, swollen breast and the feeling that you’ve caught the flu or COVID. You have a fever, chills leave you exhausted, and you worry that your breastfeeding journey is at risk. This is likely mastitis.

Mastitis is inflammation of the breast, sometimes—but not always—associated with infection. It results from a continuum:

• unrelieved engorgement that progresses to a blocked duct,
• then to inflammatory mastitis,
• and in some cases to infectious mastitis, especially if an entry point for infection (such as an infected nipple crack) has not been resolved for several days.

Your breastfeeding journey is not ruined because you have mastitis. It’s not your fault. It’s your body signaling that something needs adjustment. And even if the pain makes you want to give up entirely, caution and patience are key. First, address the inflammatory episode before deciding what comes next—if that is your wish.

Even before a fever appears, mastitis often begins with:

• a sensitive, painful area on the breast,
• a localized hard spot,
• skin that becomes red and warmer,
• discomfort during breastfeeding.

Put your baby to the breast more often than usual, apply gentle heat before feeds and cold afterward if it brings relief (many mothers prefer heat). You will often see significant improvement within 24 hours.

Acting at these early signs can often prevent progression to fever and the need for antibiotics.

Mastitis never happens without a reason. It is almost always linked to incomplete drainage of the breast.

The main causes include:

• Suboptimal baby positioning (ineffective breast drainage)
• Feeds that are too widely spaced (avoid gaps longer than 6 hours between feeds or pumping)
• Pressure on the breast (underwires, bag straps, sleeping on your stomach)
• Nipple cracks that allow bacteria to enter

You may hear that “stress blocks milk” or that “fatigue causes fever”: this is false. Stress and fatigue do not cause mastitis, even though they can make feeding less effective if you are tense.

A blocked duct is like a small roadblock: milk flow is hindered, but inflammation remains localized. You feel a hard, painful lump, often without fever. If drainage improves, it resolves quickly. Pain can be intense but is not accompanied by fever.

Mastitis is more severe. You notice a red, hot, painful area and may develop fever and feel unwell—signs that inflammation is more advanced.

For years, practices now considered aggressive were recommended. You may have been told to massage the breast very firmly, tightly bind your breasts, or stop drinking fluids.

Let me be clear:

• Do not massage your breast aggressively: it can worsen inflammation and damage tissue.
• Do not bind your breasts or wear a tight bra: this increases pressure and worsens swelling.
• Do not space out feeds to “rest the breast”: this promotes milk stasis.
• Do not avoid pumping if your baby has not effectively drained the breast.
• Do not fear oversupply: the opposite is more likely.
• Do not self-medicate with antibiotics or anti-inflammatory drugs.

Instead, choose gentle, moist heat: a warm wet cloth, a warm shower before feeding, or a diaper filled with warm water applied for a few minutes can help milk flow without irritating the breast.

For a long time, mothers were advised to change feeding positions to point the baby’s chin (or nose) toward the painful area.

Studies show there is no strong evidence that this speeds recovery. What truly matters is frequent, comfortable feeding and reducing milk stasis and inflammation—not “emptying” a specific duct.

You don’t need to contort yourself so your baby’s chin points exactly at the red spot. Forget the “wolf position”! Comfort and effective feeding are what matter most.

• Massaging the breast until bruising occurs
• Spacing out feeds
• Sudden weaning
• Self-medicating with antibiotics

• Continue breastfeeding—switch to “open bar” mode.
• Before feeds: gentle, moist heat.
• After feeds: cold if it brings relief.
• Pump if your baby is unable to nurse.
• Rest, hydrate, and take care of yourself after draining the breast.
• If fever persists or there are infected lesions, consult a healthcare professional.

It’s an often-overlooked detail, but bra choice matters. A wire-free, soft, well-fitted bra reduces pressure points on the breast and lowers the risk of blocked ducts. Choose a supportive model without compression. There’s no need to wear one at night.

• Academy of Breastfeeding Medicine. Protocol #36: The Mastitis Spectrum, Revised 2022
• WHO/UNICEF. Ten Steps to Successful Breastfeeding
• Amir LH. ABM Clinical Protocol #4: Mastitis. Breastfeeding Medicine, 2014
• Wilson E, Woodd S, Benova L. (2020) Incidence of and risk factors for lactational mastitis.
• Douglas P. Does the Academy of Breastfeeding Medicine's Clinical Protocol #36 “The Mastitis Spectrum” promote overtreatment? Int Breastfeed J. 2023.