By Krista Gray, IBCLC. Last updated February 13, 2013.

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What is mastitis?

Mastitis is inflammation of the breast. It occurs when milk is not effectively removed from a duct, leading to a plugged duct. Mastitis symptoms are more severe than just having a plugged duct.  It can be caused by infection or a blocked duct. If it is infective mastitis, it should be treated with antibiotics. However, many cases can be effectively managed with good breastfeeding techniques.


Symptoms may include one or more of the following:

  • Tenderness
  • Breast lump
  • Pressure/pain build up
  • Skin may be warm and red, possibly with a red streak following the blocked duct
  • Fever (38.5 C/101.3 F or higher)
  • Tired, run-down
  • Achy, flu-like feeling
  • Typically in one breast only
  • Even after duct is drained can be sore and feel bruised for several days


  • Scheduled nursing
  • Restrictive items on chest: tight-fitting bras, especially underwire bras, certain slings, tight-fitting tops, sleeping positions, holding a heavy diaper bag while shopping (which can put pressure on a duct), etc.
  • Engorgement
  • Ineffective milk removal
  • Poor latch – which can lead to misshapen nipples, nipple pain, and/or ineffective milk removal
  • Nipple bleb – which can obstruct the removal of milk from a duct
  • Cracked nipples – which can allow for infection (poor latch or nipple piercings could be causes of cracking)
  • Stress
  • Missing feeds – perhaps baby slept longer and missed a typical feed or mom was away and bottle was given
  • Outside distractions – perhaps mom was exceptionally busy (happens frequently around holidays) and forgets to nurse as often
  • Rapid weaning – where breasts are more prone to engorgement
  • Overabundant milk supply
  • Previous bouts with mastitis
  • Breast surgery/anomalies – from prior breast surgeries, for example, where a duct may be blocked from scarring; or a lump that is already in the breast*

*If a mom continues to have recurring bouts of mastitis in the exact same location it may be from an internal breast issue. She should check with her doctor to find out the root cause.


The most important thing you can do to resolve mastitis is to frequently and effectively remove milk from your breasts. Therefore, it is important to breastfeed often! Even if you are prescribed antibiotics, make sure you continue frequent breastfeeding. Keeping the milk flowing can prevent a plugged duct from turning into mastitis or mastitis from turning into an abscess. This is not the time to wean your baby! (Unless otherwise directed by your doctor, many cases of mastitis can be cleared by following these strategies, without the use of antibiotics.)

10 Strategies to Help with Mastitis

  1. Drain your breasts often. Drain the affected breast at least every 2 hours – but don’t neglect the other side either.
  2. Get plenty of rest. Ideally, go to bed with your baby!
  3. Drink plenty of water and eat nutritious whole foods – to boost your immune system.
  4. Use warm compresses before nursing – either take a shower, dip the breast in warm water, or use wet heat from a water bottle, etc. Gently remove any dried milk from the nipple before nursing.
  5. Use breast compressions while nursing.
  6. Since mastitis is inflammation of the breast, applying cold compresses after nursing can also bring comfort.
  7. Occasionally nurse your baby while he is on his back and your breast is dangling above so that gravity can help to unblock the duct. Frequently change nursing positions to aid milk removal from all ducts in breast.
  8. Massage and hand express in warm water.
  9. Hand express or pump if baby is not feeding effectively.
  10. For pain, taking either acetaminophen or ibuprofen as both are safe during lactation. (Ibuprofen may be preferred as it is also an anti inflammatory.)

If mastitis symptoms have not improved within 24 hours, antibiotics will most likely need to be started as the inflammation can turn into bacterial mastitis. Milk that is not drained from the breast but instead stagnates in a duct allows bacteria to multiply.  If, after 24 hours of working to unplug the duct, your symptoms have not improved or are worse, make sure to contact your health care provider.  There are also a number of measures you can take to prevent mastitis from occurring.

Symptoms of bacterial mastitis

  • Red streak running on breast
  • Pus draining from nipple crack
  • Pus or blood in milk
  • A fever that quickly spikes
  • Inflammatory mastitis that does not begin to improve after 24 hours.


Contact your health provider to discuss whether or not antibiotic treatment is needed. There are several different drugs that can be safely prescribed while breastfeeding and are effective to treat mastitis. Once you begin antibiotics, you should notice significant improvement within 48 hours. If you do not, contact your doctor as you may need to have your milk cultured and take a different medication.

Do all cases of mastitis need to be treated with antibiotics?
No, many times women can effectively treat inflammatory mastitis with rest, frequent and effective milk removal, moist, warm heat before nursing, breast massage during feeds, cold compresses and/or cabbage leaves for the inflammation between feeds, etc. The most important of these is rest and frequent milk removal from breasts.

Though sometimes the inflammation will turn into a bacterial infection that requires antibiotic treatment, the antibiotics don’t address the original cause of why a mother got mastitis in the first place. See causes (above) to help figure out why you were likely susceptible.

Research also has shown that frequent and effective removal of milk alongside antibiotics is more effective at decreasing symptom duration than antibiotics alone.

What happens if my baby refuses to nurse on the side with mastitis?
When a mother has mastitis, the milk tastes saltier to her baby. Sodium and chloride levels rise in mother’s milk and some babies will reject the taste of this milk and prefer to nurse on the unaffected side only. (Please note that it is still completely safe and nutritious for baby to consume milk from a breast with mastitis.) If you are unable to encourage your baby to nurse on the affected side, continue breastfeeding on the unaffected side and express milk regularly from the side that is blocked. Once the blockage is cleared (either through frequent feeds or antibiotics) the milk will return to its regular flavor and your baby should easily go back to nursing on both sides.

If you happen to be pumping, rather than nursing at the breast, when the duct unclogs you may notice thicker, spaghetti-like milk come out.  It is just fine for your baby to drink this.  Any infection in this area of your breast is neutralized by the anti infective properties in your milk so there is no caution required when nursing your baby.  In fact, nursing (or pumping) often is the key to treating a clogged duct/mastitis!

I am exhausted and in pain. . . maybe I should wean my baby?
When you have mastitis is definitely NOT the time to wean your baby. The most effective way to treat mastitis is by nursing your baby – frequently. Ask for help with your older children and household responsibilities and try to just go to bed with your nursing baby. This way you get rest and can easily nurse often.

Recurrence Rates

A history of mastitis does tend to be a risk factor for recurrence. Most cases appear in the first few weeks after birth, when it is common for a woman to have more milk than her baby is able to drink. However, mastitis and plugged ducts do not have to be limited to this time. A woman can get it at any time. Another common time is during weaning – again when feeds tend to be more scheduled and breasts have the opportunity to become full or engorged.

If you have a re-occurrence within a few weeks, it is quite possible the original mastitis was not completely cleared. Be diligent with home treatments to clear mastitis completely. If you take a course of antibiotics, make sure to complete the full course. Ideally, you should have a 10-14 day prescription.

If you seem to have recurring bouts with plugged ducts, taking lecithin may help.

Complications and Concerns with Mastitis

When the breast has inflammation with mastitis, milk production is slowed. It is not only important to nurse frequently and effectively to remove the blockage, but continue to diligently nurse often on the affected side for a few days following the dissipation of symptoms in order to increase milk supply again.

It is important to treat mastitis quickly and effectively. If it is left untreated, or recurs often enough, it can cause reduced milk supply as the ducts that are continuously blocked shut down altogether. This can lead to a fussy baby and early weaning.

If the mastitis is treated with antibiotics, be aware that a candida overgrowth could form.

In severe cases of infectious mastitis, an abscess can develop in the breast.