What is Mastitis?

Your breasts are bound to be tender and slightly swollen once they start filling with milk. To new mothers who are breastfeeding for the first time, you might think that a lot of pain and tenderness is normal—but it’s not. If one or both breasts are inflamed, painful, and you feel like you have come down with a case of the flu, you could have mastitis.

Because mastitis needs treatment, it is important to know the causes, symptoms, risks involved. Here is everything you need to know about mastitis.

What is Mastitis?

Mastitis is the medical name given to breast inflammation that is usually caused by an infected milk duct. Any female can develop mastitis, but the possibility is highest at the start of breastfeeding. The first 2-3 weeks are the riskiest. About 20-percent of mothers will experience mastitis at least once in their lifetime.

The good news is that, while mastitis is painful and can leave you feeling fatigued and uncomfortable, nursing your baby during this time is perfectly fine. Breastfeeding may even help with clearing up the infection.

What Causes Mastitis?

If you don’t want to be one of those people who develop mastitis, then you need to know what causes it. Mastitis is caused by a plugged duct. Now, blocked milk ducts and blebs, or milk blisters, are very common, and these two conditions are often where the infection starts.

Plugged ducts happen when a duct becomes blocked and milk can no longer flow easily. The area where the blockage is located may be tender and painful to the touch. When the blockage doesn’t get treated, an infection can occur.

How do plugged ducts happen? There are two reasons:

  • You are wearing too tight clothing or a tight, underwire bra.
  • Your breasts are engorged. Engorgement occurs when there isn’t enough milk being removed from the breasts, whether that is caused by oversupply, infrequent feedings, your baby’s latch, skipping feeding, teething, and other things.

Preventing Blocked Ducts

Since plugged ducts are connected to mastitis, preventing blockages is the main way of effectively your risk for mastitis. Here are some ways to avoid blocked ducts:

  • Wear loose-fit clothes and avoid using a bra during the first couple of weeks of breastfeeding.
  • Don’t wear a bra unless you absolutely must.
  • Give your baby unlimited time with your breast. If you are finding it difficult to make time for breastfeeding or are prevented from feeding during visitations, then you can either ask the guests to leave or let fewer people into your house. Don’t let others make you feel uncomfortable about breastfeeding.
  • Continue feeding and pumping your breasts as often as you can so you don’t skip feedings.
  • Understand proper breastfeeding techniques. You may also have to test your baby’s latch. A better latch will assist with emptying the breast and avoid other painful side effects, such as cracked nipples and blebs.

Other Causes of Breast Infection

Pay attention to sore, cracked, and bleeding nipples, because this can become a point for bacteria to enter and infect your breast. If you frequently deal with sore nipples, be careful with head positioning during feeding and the latch. Should your baby be having trouble with latching or have a tongue-tie, you can get assistance from a local lactation consultant or your doctor.

If you are using nipple shields often, you may want to stop, especially if you are at risk of developing mastitis. Nipple shields will slow milk flow, encouraging blocked ducts and, thus, infection. Additionally, giving your baby a pacifier or an artificial nipple will affect how they suck, and that can also contribute to soreness and breast inflammation.

Lastly, consistent pressure applied to the breast can often cause soreness. This does not solely mean clothing. Even shoulder straps from seat belts or heavy purse straps can affect your breasts. Sometimes a kick to the breast from an energetic toddler, for example, can also cause swelling in the breast tissue and restrict blood flow, leading to a plugged duct.

What Are The Symptoms of Mastitis?

The symptoms of mastitis may appear slowly and will usually begin in a localized area of the breast, typically at the blockage. Your breast may be inflamed, red, and hot to the touch. You may even feel a hard lump in your breast. Many women also report feeling achy, as if they have the flu. Some get the chills and a fever.

As mastitis worsens, symptoms progress. For example, the lymph nodes under the armpit will start to swell. Your heart rate will increase with the stress, and the flu-like effects will get more severe. Eventually, if not taken care of immediately, mastitis can lead to an abscess.

An abscess is pus that has collected within the body and can cause further redness, pain, swelling, and tenderness. The swollen lump might feel like it is full of fluid. You might need to have the abscess drained.

What Increases The Risk of Developing Mastitis?

Some people have a higher chance of getting mastitis than others. The risk factors include:

  • Previous experience with mastitis.
  • A history of breast surgery, lumps, or injury to the breast increases the risk of infection.
  • Delaying or skipping breastfeeding and pumping.
  • Cracked, irritated nipples, which are usually the result of poor head positioning or poor latching.

Keep in mind that the symptoms of mastitis can develop at any time during breastfeeding, even after you have successfully gotten through the first 6 weeks (about 2 months).

Caring For Mastitis

If you have the symptoms of breast infection and knew that you had a plugged duct, then you can immediately start with home treatments. The steps you should take to care for mastitis are:

  • Rest and avoid strenuous activities
  • Stay hydrated
  • Use a warm compress on the breast prior to feedings to assist with drainage
  • Alternate between massaging your breast and compresses during breastfeeding and even during downtime to help move milk through the ducts
  • Feed your baby 8-12 times throughout the day, from both breasts
  • If your baby cannot drain the milk fully from the affected breast, you should either express with a pump or by hand to get all the milk out
  • Get in contact with your doctor to see if you should use anti-inflammatory medication for the pain and swelling

Yes, you can continue feeding your baby! It is just a myth that feeding your baby during a breast infection is unhealthy. There are antibacterial properties in human breastmilk that will help with soothing the infection. Continuing the feedings when experiencing a plugged duct or mastitis can actually accelerate healing and recovery.

Nursing is one of the best things you can do whenever you develop a blocked duct or bleb because it encourages the plugged duct to open up. You may need to change up breastfeeding positions to ensure all areas of the breast are being drained effectively. If you are having trouble finding the most beneficial position, you can contact a lactation consultant to help you.

Keep in mind that rest is also very important when you are ill. Rest with your baby beside you in bed and keep necessary items, such as extra diapers, your phone, water, and toys to minimize movement.

In the event that a home remedy is not enough, you may have to schedule an appointment with your doctor. Signs that home treatment is failing include:

  • Symptoms persist for the next 8-24 hours or longer
  • You continue to have a high fever or the temperature spikes to 101° F (38.4° C) or higher
  • There is blood and/or pus in the breastmilk
  • Your breast becomes even redder and more swollen
  • Red streaks are running from the breast towards your underarm
  • Cracked nipples start to look infected
  • You develop chills or the flu-like symptoms worsen

Don’t wait for mastitis to get better at this point. You will need medical care to ease the symptoms and clear the infection.

Recurring Mastitis

Although most women will never want to experience mastitis even once, some women tend to develop breast infections more often than others. If you are getting recurring mastitis, you are likely being too cautious or have long stretches of time between breastfeeding sessions. You should also periodically change the way you are holding the baby to ensure all the milk ducts are being emptied.

The other reason mastitis develops again is when the bacteria from the first infection is not sensitive or entirely resistant to the antibiotic you were prescribed. Furthermore, if the antibiotics are not used long enough or if an incorrect medication is prescribed, the bacteria might not be dealt with completely.

Mastitis can also recur if you avoid nursing on the affected side or when the initial cause of the infection was not properly addressed. For example, if caused by milk stasis, you will need to have that milk removed.

In the event you get mastitis again, be sure to ask your doctor to do a milk culture. A culture can help pinpoint what kind of bacteria is involved in the infection. Many organisms are becoming resistant to common antibiotics, and repeatedly using ineffective prescriptions risks the development of an abscess.

Methicillin-resistant Staph aureus (MRSA) is becoming a more common cause of mastitis. You can become exposed to MRSA in the hospital (also known as hospital-acquired MRSA). Risk factors include cesarean delivery (C-section), receiving antibiotics during the peripartum period, having experienced in vitro fertilization, and experiencing multiple gestations. Outpatient MRSA is also possible but less common.
Diagnosis and Treatment For Mastitis

If you are unsure if you have mastitis or your symptoms have worsened, contacting a medical professional is your best bet. Your doctor can help diagnose the cause of the pain and swelling. They will also run a culture of your breastmilk to figure out which antibiotic is correct for you. If they don’t do this, ask for one.

There is a rare form of breast cancer that can cause redness and swelling and is often confused for mastitis. Because of this, your doctor may also request an ultrasound, mammogram, or both.

Once the results have come back, you will most likely be put on antibiotics and pain relievers. Antibiotics often last for 10 days. Finish the antibiotics to reduce the chances of developing mastitis again.

Overall, the prognosis for mastitis is excellent. Simply vary breastfeeding positions, hold frequent breastfeeding sessions, and be sure to drain your breasts—especially the infected one—completely.


What is mastitis? Hopefully, you now know that it is an infection of the breast most often caused by a blocked milk duct. If your breasts are red, swollen, and you feel as if you have the flu, you may have an infected breast. Follow the tips in this article to help, but keep in mind that if symptoms get worse, you may be in need of antibiotics.

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