A blocked (or plugged) milk duct (also known as ductal narrowing) can occur when milk flow is restricted by swelling of the breast(s) when too much milk is being made. This can cause your breasts to become inflamed and sore.

If a blocked milk duct is not treated and gets worse, it might develop into mastitis.

Blocked milk ducts

Signs and symptoms

Common signs and symptoms of blocked milk ducts include:

• An area of your breast becomes red, hard and painful.
• A painful white blob/spot on your nipple. Ask your GP, child health or lactation consultant for more information on white spot.
• Your milk may have strings of thickened or fatty-looking milk.

Mastitis

Mastitis can be caused when blocked milk ducts are not treated quickly. There are two types of mastitis – inflammatory and bacterial.

Inflammatory mastitis can develop from continuing or worsening blocked milk ducts.

Symptoms

• Increasing redness, hardness and pain in your breast.
• General symptoms such as fever, chills and fast heart rate.

Note: These symptoms can occur without an infection.

Bacterial mastitis can develop from continuing or worsening ductal narrowing and inflammatory mastitis.

Symptoms

• Worsening redness, pain and hardness in an area of your breast.
• Continuing fever and fast heart rate lasting longer than 24 hours.

When to seek help

See your GP if you have been unable to relieve symptoms after 24 hours.

In an emergency, call Triple Zero (000) and ask for an ambulance.

If you're not sure whether to go to an emergency department, call 13 HEALTH (13 43 25 84) and speak to a registered nurse.

Treatment

• The most important part of treatment for blocked milk ducts and mastitis is to reduce swelling (inflammation). Place covered cold packs on the breast to reduce swelling.
• Continue to feed your baby on demand. You do not need to “empty” your breast. If you are expressing milk to feed your baby, continue with your usual expressing routine.
• Gentle massage, sweeping towards the armpit may help to reduce swelling. You have lymph nodes in your armpits that can help drain away excess fluid.
• Avoid firm massage which may increase swelling

Medications

• An anti-inflammatory drug such as ibuprofen, can help with symptoms such as pain, redness and swelling.
• Paracetamol can be taken with ibuprofen. Always use as directed.
• Sunflower or soy lecithin 5-10 grams daily may reduce inflammation in ducts.
• Antibiotics are not usually needed to treat a blocked/ plugged duct (ductal narrowing) or inflammatory mastitis.
• If antibiotics are required to treat an infection in your breast, it is usually still safe to continue breastfeeding or expressing milk for your baby.
• Consider taking a probiotic after you have finished your course of antibiotics.

Care at home

Management before breastfeeding or expressing

• Gentle massage of the breast.
• Hand express if needed to soften the areola (area around the nipple), this may help your baby to latch well to the breast.

Management during breastfeeding or expressing

• Gentle massage during breastfeeding/expressing.
• Milk supply from your affected breast may decrease temporarily.
• Baby may be fussy while breastfeeding due to a change in milk taste (e.g., salty).
• If you are expressing, check that the breast pump is positioned correctly, and the kit is the correct size.
• It is important that your baby is latching well. If you need help, see your local Child Health Nurse or a Lactation Consultant.

Management after breastfeeding or expressing

• Place cold packs on effected breast for up to 10 minutes, repeat every hour, or more often if needed.
• If needed, express a small amount of milk to remain comfortable.

After mastitis has resolved, the affected area may still feel tender for a few more days.

To avoid further problems with blocked/plugged ducts

• Wear a well-fitting supportive bra.
• Avoid sleeping on your stomach.
• Avoid going for long periods without either breastfeeding or expressing.
• Drink water to satisfy thirst and rest when possible.
• Breastfeed as often as your baby needs (normally 8-12 times in 24 hours).
• Avoid over breastfeeding or expressing extra milk if you already have too much milk.

Key points

• Continue to feed your baby on demand, you do not need to ‘empty’ your breast.
• If you are using expressed milk to feed your baby, continue with your usual expressing routine.
• Milk volumes work on a ‘feedback mechanism’. If milk is removed, your body tries to replace it. Increasing milk removal can result in increased milk production and cause more swelling.
• If you have been unable to relieve symptoms after 24 hours, you may have bacterial mastitis and you should see your GP.

For more information

• Lactation Consultants of Australia and New Zealand  
• Australian Breastfeeding Association
• BFMed Protocols

Developed by the Lactation Service, Queensland Children’s Hospital. We acknowledge the input of consumers and carers.

Resource ID: FS127. Reviewed: March 2023.

Disclaimer: This information has been produced by healthcare professionals as a guideline only and is intended to support, not replace, discussion with your child’s doctor or healthcare professionals. Information is updated regularly, so please check you are referring to the most recent version. Seek medical advice, as appropriate, for concerns regarding your child’s health.