What is mastitis?

Mastitis is an inflammation of a woman's breast tissue. It commonly occurs within the first three months of breastfeeding an infant. It typically causes pain and redness in the breast.


A body’s protective immune response to injury or infection. The accumulation of fluid, cells and proteins at the site of an infection or physical injury, resulting in swelling, heat, redness, pain and loss of function.

Signs and symptoms

Signs and symptoms associated with mastitis include:

  • Discomfort or pain in the breast;
  • A red and swollen wedged area on the breast;
  • A blocked milk duct or lump;
  • Shivers and aches;
  • High temperature or fever, and;
  • Tiredness and weakness.

Redness on breast due to mastitis.Mastitis can cause a red and swollen wedged area on the breast. 


Mastitis is caused by an infection in the breast. It begins with a duct in the nipple becoming blocked, usually in breastfeeding mothers. Bacteria from the surface of the skin or baby's mouth get trapped in the blocked duct or enter via cracked nipples. These bacteria infect the mammary glands, giving rise to the symptoms of mastitis.

Stages causing mastitis.The three stages leading to the development of mastitis. 


Microscopic, single-celled organisms with DNA but no definite nucleus. Bacteria are the cause of many human diseases.


Entry into the body of microorganisms that can reproduce and cause disease.

Risk factors

Risk factors associated with developing mastitis include:

  • Prior mastitis;
  • Blocked duct due to poor breast drainage from improper attachment of the baby to the breast;
  • Cracked nipples (though it can also occur without cracked nipples), and;
  • Restricted milk flow from tight clothing.

Methods for diagnosis

Mastitis can be diagnosed by your doctor after a physical examination and observation of your signs and symptoms including fever, chills and tenderness of the breast. A red, tender wedge-shaped area on the breast is also an indicator of mastitis.

Types of treatment

It is important to begin treatment at the first signs of mastitis. Mastitis is commonly treated with oral antibiotics to fight the infection. It is important to tell your doctor if you are allergic to penicillin. Pain-relief medication, such as acetaminophen, can also be used. Other treatment steps include:

  • Continuing breastfeeding from the affected breast. This is important and is safe for your baby;
  • Keeping the breast well drained through feeding or expressing;
  • Heating the sore area of the breast before feeding. This can be done with a warm shower, hot water bottle or warm face washer;
  • Cooling the breast after feeding. This can be done with an icepack wrapped in cloth;
  • Massaging any lumps within the breast towards the nipple while feeding;
  • Getting enough rest, and;
  • Eating a healthy diet and drinking plenty of water.


Entry into the body of microorganisms that can reproduce and cause disease.


A group of antibiotics used to treat a variety of bacterial infections.

Potential complications

If mastitis is identified and treated early, the condition will generally improve within 48 hours. Without prompt treatment, a breast abscess may develop that may require drainage. This is performed by a doctor and involves insertion of a needle into the breast in a process called aspiration.

There is also a risk of an infection with candida (thrush), particularly after using antibiotics. This condition causes breast pain, especially during and after feeding.


Entry into the body of microorganisms that can reproduce and cause disease.


Mastitis is a temporary and treatable condition. Although it can be quite painful at first, treatment with antibiotics is very effective and fast acting. It is important to begin treatment as soon as possible to avoid the condition worsening and an abscess forming.


To help prevent mastitis, it is important to ensure that milk is draining well. Blocked milk ducts can be due to missed feeds, the breast not draining well, or the wrong feeding position. If there is an oversupply of milk, you can speak to your health provider to discuss the best ways to manage this. It is possible to reduce the level of milk by expressing milk by hand or with a breast pump. Trying to get rest while your baby is asleep is also good for your wellbeing.


  1. Association Australian Breastfeeding. Mastitis. Australian Breastfeeding Association July 8 2011. link here
  2. Breastfeeding - Dealing with Mastitis. Better Health Channel. Accessed August 1 2014. link here
  3. Mastitis. The Royal Womens Hospital. Accessed August 1 2014. link here
  4. Murtagh John. Murtaghs Patient Education. Australian ed of 6th revised ed edition. North Ryde N.S.W.: McGraw-Hill Australia 2012.
  5. Murtagh John MD. John Murtaghs General Practice. 5th Revised edition edition. North Ryde N.S.W.: McGraw-Hill Medical Publishing 2011.

FAQ Frequently asked questions