Mastitis and breast abscess

Also known as breast infection

Mastitis is inflammation or swelling of your breast tissue, particularly the milk ducts and glands in a breastfeeding woman.

On this page, you can find the following information:

Key points about mastitis

  1. Mastitis is common, occurring in approximately 1 in 5 women. It is usually due to an underlying issue that needs to be identified and addressed. 
  2. Mastitis most often happens in the first 4 weeks of breastfeeding when cracked nipples, positioning problems and breast engorgement are most common.
  3. Your commitment to breastfeeding will be tested during this time, but continuing to breastfeed is often part of the solution and stopping can make the mastitis much worse. 
  4. Talk to your doctor or midwife if you get a sore breast, a tender red, lumpy area in your breast or feel unwell with 'flu-like' symptoms.
  5. There are also things you can do to ease symptoms, such as continuing to breastfeed, applying wet or dry heat and gentle massage, rest and pain relief.
  6. See your doctor straight away if you have a fever, as you may need antibiotics to treat an infection.

What are the types of mastitis?

There are 2 types of mastitis: non-infectious mastitis and infectious mastitis. 

Non-infectious mastitis

This type of mastitis is usually caused by breast milk staying within the breast tissue. This happens because of a blocked milk duct or a breastfeeding problem. If left untreated, the milk left in the breast tissue can become infected, leading to infectious mastitis.

Infectious mastitis

This type of mastitis is caused by bacterial infection. It is important to receive treatment immediately to prevent complications, such as an abscess in the breast.

You can get infectious mastitis even when not breastfeeding. 

What are the causes of mastitis?

Milk stasis

When milk isn't completely emptied from a breast at feedings, the milk left in the breast tissue can back up and become infected. This is known as milk stasis.

Milk stasis may be caused by:

  • poor latch on and/or effective sucking by your baby
  • inefficient positioning between mother and baby during breastfeeding  
  • scheduled or restricted feeds, long gaps without feeding, missed or short feeds
  • sudden cessation of breastfeeding
  • overabundant milk supply
  • breast engorgement
  • blocked milk duct
  • pressure on a particular area of the breast caused by a tight bra, gym/swimwear, breast shells, car seatbelt, bag strap across your breasts, your sleeping position or holding your breast firmly during feeding
  • stress and fatigue that leads to less time for breastfeeding 
  • separation from baby
  • sleep training programmes that discourage night-time breastfeeding
  • unusual stress and fatigue or a weakened immune system in the mother.

Bacteria entering your breast

Bacteria from your skin's surface and baby's mouth can enter the milk ducts through a break or crack in the skin of your nipple or through a milk duct opening. Bacteria can multiply, leading to infection. These germs aren't harmful to your baby – everyone has them. They just don't belong in your breast tissues.

Nipple damage may be caused by a baby not being latched on correctly or having a tongue tie. In rare cases, untreated dermatitis of your nipple or surrounding area can be the cause. 

What are the risk factors for mastitis?

You are more likely to get mastitis if you:

  • have nipple damage
  • experience increased and sustained engorgement of your breasts
  • have a history of problems with latching your baby on your breast
  • are stressed and exhausted
  • have missed feedings and milk stasis
  • have a previous mastitis history with other babies
  • use a manual breast pump.

What are the symptoms of mastitis?

While mastitis is common in the first month of breastfeeding, it can also occur at any stage when you are lactating and particularly when the number of breastfeeds or milk expressions is suddenly reduced.

Symptoms of mastitis include:

  • sore breast
  • lumpy area that is usually red and tender
  • fever (a temperature)
  • chills
  • feeling unwell with 'flu-like' symptoms, such as tired, aching, run-down).

Most cases of mastitis are caused because your baby is not latched on or positioned on your breast correctly. This leads to milk stasis, with blocked milk ducts and alveoli, and nipple trauma.

What is the treatment for mastitis?

The following are the key ways of managing mastitis:

  • Empty your breast by breastfeeding on the affected side. If this is not possible, hand express or use a pump to help get the milk moving.
  • Try gentle massage. Doing this under heat can be helpful to liquefy the fat within the milk and help move it through. This is best done in a shower. 
  • Use cold compresses after feeds.
  • Get rest.
  • Consider taking ibuprofen to help with swelling and pain. This is compatible with breastfeeding. However, always check with your doctor if you are considering other anti-inflammatory pain-relief medicines. 
  • Get medical help if these self-care steps don't work for you.

See your doctor or midwife straight away if you have a fever, as you may need antibiotics to treat the infection.

  • Flucloxacillin 500mg 4 times per day (at least an hour before food), is the most commonly used antibiotic.
  • If you are allergic to penicillin, you must tell your doctor/midwife as a different antibiotic will be needed.

If you don't improve within 24 hours of treatment, seek further medical advice.

If you have had all the appropriate treatment for mastitis and an area of your breast remains hard, reddened and painful, a breast abscess may have formed or be forming.

If this happens, see your doctor for treatment. Read more about breast abscess.

What can I do to manage mastitis?

Empty your breast

  • Breastfeed on demand, starting with the sore breast.
  • Make sure your baby is latched on correctly (mouth covering almost the entire areola, not just the nipple) and drains your breast well.
  • Make sure your breast feels soft and comfortable after feeding.
  • It is recommended and safe to feed your baby from the affected breast.
  • Try different feeding positions to improve drainage (baby's chin near the inflamed area).
  • Wear loose-fitting clothes and a bra that is well-fitting and does not dig in anywhere (obstructing the flow of milk).
  • Change breast pads or bras frequently if you are leaking milk.

Gentle massage and compresses

  • Warm compresses could be used to assist milk flow before feeding or expressing (eg, a warm shower, or covered hot water bottle, or wrapped wheat bag). Make sure none of these are too hot.
  • Gentle massage of the affected breast and lying flat prior to a feed can be helpful. The fingers (not tips) can be used in firm stroking movements towards your sternum and armpit.
  • Care must be taken to avoid massage that is too firm as this can cause trauma and undue pressure and increase inflammation.
  • Cold packs can also be quite soothing when placed on the breast after feeding.
  • A soft stretchy support such as tubigrip or boob tube may be better than a bra at this time.

Rest and pain relief

  • It is very important that you have time to rest and spend time feeding your baby properly.
  • Ask your partner, family or whānau for more support so you can rest and recover.
  • If you do not have good support, ask your midwife or Plunket nurse to help you find some support.
  • Drink plenty of fluid (especially if you have a fever).
  • Take the full course of antibiotics prescribed even if you feel like you are better. This will ensure that the risk mastitis reoccurring in your breast is reduced.
  • Paracetamol can be taken every 4 hours if necessary for pain and fever. Ibuprofen can also be helpful.

Expressing blockages

If you are unable to latch your baby properly, or express your milk normally, you may opt to express the blockage yourself. Sometimes, during gentle massage, you can even accidentally express it!

The coagulated milk responsible for the blockage may look like a rock, grain of sand or even a strand of spaghetti. If your baby clears this blockage during breastfeeding, this is not harmful.

Breast lumps

During pregnancy, your breasts may feel lumpy. This is usually because the glands that produce milk are increasing in number and getting larger in preparation for breastfeeding. However, because 1 in 9 New Zealand women develop breast cancer in their lifetime, see your doctor if you notice any changes in your breasts. Read more about breast lumps and changes

Support for mastitis

You can phone Plunketline on 0800 933 92 anytime day or night for advice about breastfeeding. You can also talk to your midwife, doctor or Plunket nurse

If you are still having breastfeeding problems, ask your midwife if you should be referred to a lactation consultant.

Other groups to contact include La Leche League NZ, your local Parents Centre NZ and Kellymom – an American lactation consultant website and Facebook Support Group.

Learn more 

Mastitis and breast abscesses Ministry of Health, NZ
Breastfeeding – wide range of resources Ministry of Health, NZ 

Credits: Health Navigator Editorial Team. Reviewed By: Dr Stella Lisle, Canterbury DHB Last reviewed: 27 Oct 2020