Mastitis and breast abscess

Also known as breast infection

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

Key points

  1. Mastitis is common, occurring in approximately 1 in 5 women.
  2. It most often happens in the first 4 weeks of breastfeeding when cracked nipples, positioning problems and breast engorgement are most common.
  3. 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.
  4. There are also things you can do to ease symptoms, such as emptying your breast, gentle massage, cold compresses after feeds, rest and pain relief.
  5. 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.

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:

  • ineffective breast drainage caused by poor positioning and attachment
  • scheduled or restricted feeds, long gaps without feeding, missed or short feeds
  • sudden cessation of breastfeeding
  • over abundant milk supply
  • breast engorgement
  • blocked milk duct
  • pressure on a particular area of the breast caused by tight bra or holding the breast firmly during feeding
  • stress and fatigue which leads to less time for breastfeeding
  • separation from baby.

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 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
  • have a history of problems with latching the baby on the breast
  • are stressed and exhausted
  • have missed feedings and milk stasis
  • have a previous mastitis history with other babies
  • use of 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
  • chills
  • feeling unwell with 'flu-like' symptoms.

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 key ways of managing mastitis are for you to:

  • get medical help
  • empty your breast
  • try gentle massage
  • use cold compresses after feeds
  • get rest
  • use pain relief.

See your doctor or midwife straight away if you have 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 the breast well.
  • It is quite safe to feed your baby from the affected breast.
  • Try different feeding positions to improve drainage (baby's chin near the inflammed 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).
  • Paracetamol can be taken every 4 hours if necessary for the pain and fever.
  • Ibuprofen can also be helpful.

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: Andreea Dumitru, Senior RN from CCDHB, SIDU - Capital & Coast & Lower Hutt Last reviewed: 31 Oct 2015