Treating mastitis

What should I do if I have mastitis?

Mothers with mastitis should continue to breastfeed if they are able. They should treat themselves at home, if possible, rather than going to hospital, and ensure effective breast emptying. If breastfeeding is too painful, they need to express. Mothers can also use anti-inflammatory medication for pain and fever and cold cabbage compresses. They should see their health-care providers and discuss the use of antibiotics. Delaying antibiotics can result in the infection getting worse or an abscess developing. Nearly all antibiotics are considered compatible (pose little or no risk to the baby) with breastfeeding. Most mastitis clears within one week but it may take up to two if the mastitis is severe. Health-care providers may recommend milk testing or an ultrasound for mothers who are not getting better with antibiotic treatment. The baby's growth should be monitored during this time. 

A) Summary of treating mastitis

Severe mastitis of the right breast. The mother was treated with IV antibiotics, the mastitis cleared completely, and the mother continued breastfeeding on the affected breast.

Mothers who have mastitis should consider the following.

It is very important to not leave milk in the breast to stagnate as this will delay healing and may lead to further complications such as a breast abscess. Mothers:

  • Should continue to breastfeed.  
  • Should avoid separation from their babies.
  • Should stay at home if possible and not in hospital.
  • Can temporarily express if it is too painful to breastfeed and if they can do so effectively.
  • May find warm or cold compresses helpful.
  • Can use anti-inflammatory medication for pain and fever.
  • Can use some of the gentler tools used to stimulate the let-down before feeding.
  • Can use a warm water breast bath in a constant-suction pump to help empty the breast after breastfeeding.

They need to manage the infection and:

  • See their health-care providers to discuss if oral (pills) or intravenous (IV) antibiotics are needed.
  • Should expect mastitis to improve within a few days of starting treatment and be cleared within one week. Severe mastitis can take up to two weeks to clear.

Mothers can be quite ill and need to look after themselves. They should rest, eat well, and sleep when able.

Mothers need to watch for complications and:

  • May benefit from having their milk tested if their mastitis does not settle. 
  • May need an ultrasound or biopsy to check for an abscess, breast cancer, or other problems if the mastitis does not clear or they develop a lump in the breast. 

Mothers need to ensure that their baby is taking in enough milk during this time.

B) General care

The body quickly responds to mastitis by increasing blood flow to the area and activating bacteria-fighting systems. The area then becomes inflamed with swelling and pain. The swelling may block milk ducts both in the affected area and away from it, and pain may interfere with the let-down. 

As a result, the breast may not empty well with breastfeeding or with expressing. That causes more swelling and pain, delays healing, and increases the risk of getting an abscess.

1) Breastfeeding 

The most effective way to empty a breast is by breastfeeding when the baby is hungry, offering both breasts at each feed, and not favouring one side over the other.

Mothers can increase breast emptying by breastfeeding the baby to sleep on the breast with mastitis after the baby has breastfed on both sides. If only done for a few days until the mastitis has improved, these short and occasional feeds are unlikely to significantly increase the milk supply on the affected breast or decrease it in the normal one. If the breast with mastitis is very painful, they should use the unaffected one for this; again, this is unlikely to create significant changes in the milk supply of either breast.

Mothers can help their breast empty by using some of the gentler tools used to stimulate a let-down before feeding.

2) Warm and cold compresses 

Early or mild mastitis might benefit from warm compresses before breastfeeding to help blood and bacteria fighting-white blood cells enter the breast.

Moderately to severely infected breasts are unlikely to benefit from this as the breast is already very warm. Rather such mothers may find cool cabbage compresses helpful in reducing pain and swelling. 

3) Anti-inflammatory drugs

Anti-inflammatory drugs are compatible (pose little or no risk to the baby) with breastfeeding. They may reduce pain, fever, and swelling. 

4) Warm water breast bath in a constant-suction pump

Breast fullness after breastfeeding or expressing in the area of the breast away from the site of the infection can be a sign that the breast is not emptying well.  

In this situation, extra milk can be removed from the breast using a constant-suction pump filled with warm water. When the pump is attached to the breast, the nipple and central areola sit in warm water. This method uses the comfort of warm water to relieve pain and bring on a let-down and the suction created by the pump to draw out the milk. This is very gentle and, when done properly, is unlikely to add to a mother's pain. This can also soften the nipple root as it is slightly stretched in the pump. 

5) Avoid breast massage

Mastitis can cause swelling of the nipple root, which can interfere with latching and may be treated with nipple root massage.

Otherwise, breast massage of the infected area is best avoided as:

  • There is no evidence that it helps
  • It will be painful.
  • It may damage inflamed tissues and cause further pain and swelling. 
  • It may push infection into other areas of the breast.

C) When to start antibiotics

Antibiotics are frequently used to treat mastitis (Jahanfar 2013). Occasionally, a milder mastitis clears without antibiotics. However, delaying the use of antibiotics can result in:

  • The infection getting worse.
  • The infection lasting longer.
  • An abscess developing.

It is recommended that mothers use antibiotics if they have mastitis and notice any of the following (Amir 2014):

  • The mother feels unwell.
  • The mother has a fever.
  • The mastitis has been present for more than 24 hours without definite improvement.
  • The mastitis involves more than half of the breast.
  • The nipple skin is damaged.
  • There is a firm area developing in the middle of the area of mastitis.
  • The lymph nodes in the armpits are swollen.
  • The mother has a higher risk of infection because of diabetes, steroid use, or a weakened immune system.
  • The mother has already had mastitis.

D) Choosing an antibiotic

The choice of antibiotic depends on (Angelopoulou 2018):

  • The type of organisms that are most likely to be causing the infection.
  • The antibiotics available locally.
  • The mother's risk of allergic reactions.
  • The risk of interactions with any other medication the mother is taking.

1) Types of bacteria that can cause mastitis

Two types of Staphylococcus (aureus and epidermidis) are the most common types of bacteria that cause mastitis and abscesses. Streptococcus strains (mitis  and salivarius) are the second most likely types (Angelopoulou 2018; Mediano 2017). Other bacteria have also been reported to cause breast infections, including:

  • Methicillin-resistant staphylococcus aureus (MRSA) 
  • Streptococcus pneumonia and pyogenes
  • Salmonella
  • Enterobacteriaceae
  • Escherichia coli
  • Enterococcus faecalis  
  • Pseudomonas
  • Tuberculosis  

Some infections are caused by more than one type of microorganism. 

2) Common choices of antibiotics

It is difficult to recommend specific antibiotics because antibiotic resistance and availability varies around the world. Commonly used oral antibiotics (taken by mouth) for treating mastitis are, in order of preference:

  1. Penicillinase-resistant penicillins: cloxacilllin, dicloxacillin, or flucloxacillin
  2. First-generation cephalosporins: cephalexin
  3. Clindamycin, if there is a risk of MRSA

Other options include:

  • Erythromycin
  • Sulfamethoxazole and trimethoprim, if the baby is not premature or jaundiced

3) When a chosen antibiotic doesn't work

Different types of bacteria cause mastitis and mothers may not respond to an antibiotic aimed at one type if they are infected with another.

An antibiotic may not work if the bacterium is not susceptible (resistant) to that antibiotic (Salmanov 2020). Antibiotic resistance and availability varies around the world. Some areas have higher rates of the bacterium MRSA, which resists many antibiotics.

E) Oral or intravenous antibiotics and hospitalization

1) When intravenous antibiotics are needed

Our clinic has found that antibiotic pills generally work well and that mothers rarely need to have an antibiotic injected directly into a vein (IV). IV antibiotics may be necessary if it is a type of antibiotic that cannot be absorbed through the gut. Injection also provides higher levels of antibiotics in the blood.

IV antibiotics may be needed if:

  • The infection is very severe.
  • The infection has not responded to oral antibiotics.
  • The mother has decreased immunity.
  • The bacteria cannot be treated with oral antibiotics.

2) Intravenous antibiotics at home or in hospital

If intravenous antibiotics are needed, they may be provided in:

  • The patient’s home under the supervision of their health-care providers
  • An outpatient clinic
  • A hospital

The vast majority of mothers with mastitis do best at home while taking care of themselves by resting, drinking when thirsty, eating their preferred foods, and taking oral antibiotics if needed (Stafford 2008). This may not be an option for a mother requiring IV antibiotics.

Repeated trips to outpatient clinics for IV antibiotic treatment can be exhausting for a sick mother and should be minimized. Hospital trips may also mean the mother and baby have to be apart. The separation can lead to missed breastfeeds, which can result in:

  • The infection getting worse.
  • The infection lasting longer.
  • An abscess developing.

Some mothers are very ill and need to be hospitalized for support and IV antibiotic treatment. If a mother is in hospital, the baby should be admitted with her to avoid separation.

F) The risks of antibiotics

Antibiotic use by mothers with mastitis may cause:

  • Other infections such as vaginal yeast infections and bacterial diarrhea caused by the C. difficile bacteria.
  • Allergic reactions.
  • Changes in the mother’s gut bacteria (microbiome).
  • Antibiotic resistance.

Nearly all antibiotics are considered compatible with breastfeeding. Furthermore, the benefits of breastfeeding for babies outweigh the risks of being exposed to relatively small amounts of medication in breast milk.

G) How long to use antibiotics

There is no agreement on how long to use antibiotics, but most authorities recommend 7 to 14 days of treatment (Angelopoulou 2018). The length of time will depend on:

  • The severity of the infection.
  • The underlying cause of the infection.
  • How quickly the infection improves.

H) How long mastitis lasts

Mastitis develops quickly but also tends to clear quickly.

Occasionally, mothers will have a very mild mastitis. It should improve within 24 hours. If not, they should use antibiotics.

Mothers who are using antibiotics should feel much better within one to three days and normal within one week. Severe mastitis may take up to two weeks to fully clear.

Mothers who are not better by these times or are developing a mass should see their health-care providers as soon as possible, because:

  • They may need a different antibiotic.
  • They may need intravenous antibiotics.
  • They may be developing a breast abscess.
  • There is a remote chance they have breast cancer or other problems that can mimic mastitis.

I) Tests

Mastitis is usually diagnosed using the mother's description of the problem and by examining the breast. Occasionally, tests can be helpful. 

1) Testing the milk

Mothers may benefit from having their milk tested to see which organism is present if (WHO 2000):

  • They are not better within one week of antibiotic treatment.
  • They are allergic to the usual antibiotics.
  • The mastitis comes back.
  • The mastitis develops while the mother is in hospital.
  • The mastitis is very severe or unusual.

To collect milk for testing:

  1. Clean the nipple and areola with water and a clean cloth.
  2. Use a sterile container to collect the milk. This may be provided by your health-care provider or the laboratory that will do the testing.
  3. Use manual expression to get milk.
  4. To ensure that you collect milk with bacteria from deep in the breast:
    1. Throw out the first few drops of expressed milk and then express into your container.
    2. Lean forward when expressing into the container so that the milk has no contact with the skin of the nipple and areola and you avoid collecting skin bacteria.

2) Ultrasound and biopsy

Most episodes of mastitis clear quickly and do not return in the same area. If they do not behave in this way, there may be an underlying problem.

The most likely reason for mastitis not to settle is that an abscess, or on rare occasions a phlegmon (a localized area consisting of inflammation, infection, and pockets of fluid), is forming. This can be confirmed with an ultrasound. 

While rare, breast cancer can cause repeated episodes of mastitis in the same area.

The breast should be examined by ultrasound if the mastitis:

  • Does not improve with proper treatment within one week.
  • Develops a swollen or hard area that does not go away in a few days after starting antibiotics.
  • Returns in the same area.
  • Is unusual or very severe.

On occasion, health-care providers may need to examine the tissue of the affected area under a microscope. The tissue is obtained using a hollow needle.


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Angelopoulou A, Field D, Ryan CA, et al. The microbiology and treatment of human mastitis. Med Microbiol Immunol. 2018 Apr;207(2):83-94

Jahanfar S, Ng CJ, Teng CL. Antibiotics for mastitis in breastfeeding women. Cochrane Database Syst. Rev. 2013 Feb 28;(2):CD005458
Mediano P, Fernández L, Jiménez E, et al. Microbial Diversity in Milk of Women With Mastitis: Potential Role of Coagulase-Negative Staphylococci, Viridans Group Streptococci, and Corynebacteria. J Hum Lact. 2017 May;33(2):309-318
Reddy P, Qi C, Zembower T, et al. Postpartum mastitis and community-acquired methicillin-resistant Staphylococcus aureus. Emerg Infect Dis. 2007;13(2):298-301

Salmanov AG, Savchenko SE, Chaika K, et al. Postpartum mastitis in the breastfeeding women and antimicrobial resistance of responsible pathogens in ukraine: results a multicenter study. Wiad Lek. 2020;73(5):895-903

Stafford I, Hernandez J, Laibl V, et al. Community-acquired methicillin-resistant Staphylococcus aureus among patients with puerperal mastitis requiring hospitalization. Obstet Gynecol. 2008 Sep;112(3):533-7
World Health Organization (WHO). Mastitis: Causes and Management. Publication number WHO/FCH/CAH/00.13. World Health Organization: Geneva; 2000