Mastitis, blocked ducts, and engorgement: what to do when your breasts are inflamed

Have you got discomfort or pain from swelling in one or both breasts?

Mastitis (breast inflammation) covers a range of symptoms — from a small, tender area (often called a blocked duct) through to severe infection. This article explains what causes breast inflammation, how to treat it, and when to get help.

It’s important to act quickly to relieve discomfort and stop it getting worse. You may also need to deal with any underlying causes.

Summary

Mastitis is breast inflammation, ranging from a tender area (often called a blocked duct) to severe infection.
It is often linked to milk not flowing well — for example, ineffective feeding, long gaps between feeds, or oversupply.
Common symptoms include a painful or lumpy area, swelling, warmth, and flu-like symptoms such as fever or aches. You may also feel low or weepy — this can be part of the body’s response to inflammation.
Continuing to breastfeed, resting, and reducing inflammation may help symptoms improve within a day or two.
Seek medical advice if symptoms don’t improve, worsen, or if you feel unwell.

What do these terms mean? A quick guide

Mastitis means ‘breast inflammation’ and is now understood as a wide spectrum of related conditions.

Milk blisters/blebs look like tiny white or yellow dots on the tip of the nipple. They may cause no trouble, or they can be very painful (often described as ‘stinging’ pain). Sometimes they block milk flow from part of the breast.

They are part of the mastitis spectrum, and the same self-care measures may help. If they aren’t painful or blocking milk flow, they can be safely left alone and will usually resolve on their own

Engorgement is when the whole breast becomes swollen with extra fluid. It’s very common 2-5 days after birth, when milk production is increasing very fast, though it can happen at any stage of breastfeeding. The self-care measures described below can also help with engorgement. Managing engorgement early can help prevent mastitis.

A breast abscess is a collection of pus within the breast, caused by infection. It is usually a complication of mastitis that was not adequately treated. An abscess needs urgent medical treatment: drainage and antibiotics.

What are the signs of mastitis?

One or more tender areas in the breast (sometimes called a blocked duct).
Your breast might feel warmer, harder, or more lumpy than usual.
A patch of skin on your breast may change colour (on darker skin this may look darker than usual; on lighter skin it may appear red).
A raised temperature can happen with inflammation and doesn’t always mean you have an infection. See below: “Do I need medical help?”

Could it be a breast abscess?

Most people with an abscess feel very unwell, though not always. It could be an abscess if:

you have one or more lumps in your breast that don’t get smaller as milk is removed
the lumps don’t respond to the treatments for mastitis described in this article

Contact your GP or NHS 111 for advice. A breast abscess needs urgent medical treatment.

It’s usually possible — and may be preferable — to continue breastfeeding while an abscess is treated, if you want to. LLL Leaders can support you through this.

Why does mastitis happen?

When breasts are very full of milk, or the breast is injured, your body may respond with inflammation – a normal response to stress or damage. Blood flow to the area increases, and fluids and immune cells move in to help repair and protect the tissue.

As pressure within the breast increases, it can feel tender or painful, and milk may not flow as easily.

Common causes of breast inflammation (mastitis)

Issues with positioning and attachment: your baby is not removing milk efficiently.
Scheduling or limiting feeds: If breasts aren’t relieved as often as they need to be, this can result in mastitis (and decreased milk production). The amount of milk breasts can hold – and how long they can comfortably hold it for – varies between individuals and over time.
Oversupply: Making significantly more milk than your baby needs. This can be present from that start, or develop over time. It may be worsened by expressing milk milk than is needed. Your baby may gag, splutter, or seem unsettled when milk flows quickly. Your breasts may often feel very full. If you’re struggling with oversupply, LLL Leaders can help.
Suddenly removing less milk than usual: For example, because your baby is ill, sleeping longer, or you are away from your baby.
Weaning: if you reduce the amount you breastfeed faster than your breasts can manage.

Less common causes of mastitis

Breast injury, e.g. from a too-tight bra, bag or sling strap, breast pump, or seatbelt — or even from sleeping on your stomach.
Bacterial infection in the breast, for example through an open nipple wound.

Factors that may increase your risk of mastitis

Smoking
Previous breast surgery, such as implants
High levels of stress or extreme tiredness
Being anaemic or having other health conditions that affect your immune system
Gut health. Some research suggests that imbalances in the ‘microbiome’ (the bacteria that live in your body) may make some people more likely to develop mastitis. The breast has its own microbiome, which can be influenced by factors such as diet, antibiotic use, and whether your baby feeds direct at the breast. This is an ongoing area of research.

Causes of engorgement

In the first few days after birth, you may have more engorgement if you were given extra fluids during labour and birth. Engorgement can also happen at any stage of breastfeeding if milk isn’t moving easily.

For example, this might happen if:

your baby is unwell and feeding less than usual
your baby starts sleeping for longer stretches
you are away from your baby

My breasts are engorged, or I think I’ve got mastitis – what do I need to do?

Start managing symptoms at the first signs of breast swelling or inflammation. It’s often possible to deal with this at home without medical help.

Begin with the simplest steps: reduce inflammation, keep milk moving, and rest.

Take standard doses of an over-the-counter anti-inflammatory such as ibuprofen, if you can usually take it. Paracetamol may also help with pain. Ibuprofen is often more useful for mastitis, because it reduces inflammation. Both are safe to take while breastfeeding.
Try cold or cool compresses on the affected area between feeds, and see what feels most comfortable. Some cultures and communities recommend avoiding cold in the early weeks after birth and using heat instead — if this applies to you, see “things to avoid” below.
Remove milk as often enough to stay comfortable. Feed your baby whenever they want to feed, or continue expressing as you usually would. If your breast feels very full or uncomfortable, offer a feed or express some milk.
Rest as much as you can. Inflammation is tiring for your whole body. Mastitis often develops when you’re under extra stress or more tired than usual — it can be a sign you need to slow down. Getting help with your baby or taking time off your usual activities for a few days can support recovery.
Experiment with different feeding positions. This may help you be more comfortable and help to drain different areas of the breast.
Some experts suggest probiotics or the food supplement lecithin may help. Check with your healthcare provider or a breastfeeding supporter for current information.
Contact an LLL Leader or your local LLL group for more information and support.

Things to avoid

Some treatments that used to be recommended for mastitis don’t help, and may even make things worse:

Rough massage of your breasts. This can increase inflammation – and can be very painful. If you want to massage while feeding or expressing, use gentle touch, as if you were stroking a cat.
Applying a lot of heat, such hot showers or compresses. Heat can increase inflammation. If a little warmth helps milk flow during feeding or expressing, or makes you more comfortable between feeds, use it for short periods only. Avoid directing a hot shower straight at your breast.
Using electric toothbrushes, combs, or other devices. Trying to force milk out of the breast won’t fix inflammation and may make it worse.
Trying to remove much more milk than usual. This can increase milk production and pressure in the breast. If you need to express more milk than your baby takes, aim to express just enough to stay comfortable.

My breast is uncomfortable but my baby won’t feed

Babies sometimes refuse to feed on a breast that has mastitis.The milk is safe for your baby, but it may taste different from usual. Your baby may also be reacting to a slower flow of milk. Some people notice a temporary dip in supply during mastitis, which usually returns to normal as the breast recovers. You may need to express milk from the affected breast until your baby is willing to feed on it again.

See Nursing Strikes for ideas to encourage your baby to feed.

My breast is uncomfortable but I can’t get milk out

Don’t panic. Engorgement or mastitis can act like a traffic jam in the breast. These tips can help get the milk moving again:

Treat the inflammation by taking ibuprofen and, if helpful, applying a cold compress for 20-30 minutes before feeding or expressing.
If your baby is struggling to attach because your breast is very full and tight, try expressing a small amount of milk before offering the breast. You could also try ‘reverse pressure softening’: press firmly around the nipple with fingertips or finger lengths for about a minute before feeding. This helps move swelling away from the nipple.
Try gentle ‘lymphatic drainage’ massage, moving towards your armpit. You can watch a video demonstrating this technique here, or see the Further Reading section for more information.

Do I need medical help?

If you’re feel generally well (no fever or flu-like symptoms), you can try managing this at home for 24 hours. If your symptoms improve, you can continue for another 24 hours.

Contact NHS 111 or your GP urgently if:

Your symptoms are not improving after 24 hours, or are getting worse
You start to feel ill – shivery, shaky, or flu-like
You have a fever
A darker or red patch of skin is growing in size, or you see dark or red streaks
You see signs of infection, such as a wound that looks crusty or oozes, or changes in your nipple (shape, size, or colour).

You may need antibiotics. The NHS guidance recommends a 10-14 day course — shorter courses make it more likely that the mastitis will come back.

If you are prescribed antibiotics, continue the self-care treatments above as well as taking the medication. Contact your doctor if you are not feeling better within 48-72 hours of starting antibiotics.

Mastitis can affect how you feel

Mastitis can affect you emotionally as well as physically. Inflammation in the body can sometimes lead to low mood, tearfulness, or feeling overwhelmed.

If you’re feeling this way, it can help to know this is a common response and often improves as the inflammation settles.

Talk to someone you trust — a partner, friend, breastfeeding supporter, or healthcare professional — if you’re worried.

How can I prevent mastitis in the future?

Get breastfeeding help if you need it. A breastfeeding supporter can check for any breastfeeding issues that might contribute to mastitis.
Keep milk moving. Avoid milk building up in your breasts — feed your baby when they want, and express a little if your breasts become uncomfortable. If you have more milk than you need, a breastfeeding supporter can help.
Check your breast comfort. Make sure nothing is pressing on your breasts (see “Why does it happen?” above)
Watch out for early signs of mastitis and start self-care measures straight away.

Mastitis can feel overwhelming, and make you question whether you can carry on breastfeeding. It’s important not to suddenly stop removing milk, as this can lead to complications.

Practical and emotional support can make a big difference while you recover, along with medical care if needed. You can get through this, and you’re not alone.

Written by Jayne Joyce and Justice Reilly

Last updated: May 2026

If this article has helped you, please consider supporting LLLGB with a donation. Every gift, however small, helps keep breastfeeding information and support flowing.

References

Mastitis

Baeza, C. et al. 2022. Re: “Academy of Breastfeeding Medicine Clinical Protocol #36: The Mastitis Spectrum, Revised 2022” by Mitchell et al. Breastfeed Med 2022 17(11):970-971.

Douglas P. Re-thinking benign inflammation of the lactating breast: A mechanobiological model. Women’s Health. 2022;18. doi:10.1177/17455065221075907

Mitchell, K.B. et al.; Academy of Breastfeeding Medicine. 2022. Academy of Breastfeeding Medicine Clinical Protocol #36: The Mastitis Spectrum, Revised 2022. Breastfeed Med 17(5):360- 376. Erratum in: Breastfeed Med 2022 17(11):977-978.

NICE Mastitis and Breast Abscess (Clinical Knowledge Summary)

Last revised in December 2023Wilson, E. et al. 2020. Incidence of and risk factors for lactational mastitis: a systematic review. J Hum Lact 36(4):673-686.

Engorgement

Zakarija-Grkovic I, Stewart F. Treatments for breast engorgement during lactation. Cochrane Database of Systematic Reviews 2020, Issue 9. Art. No.: CD006946. DOI: 10.1002/14651858.CD006946.pub4.

Blebs

Douglas P. Re-thinking lactation-related nipple pain and damage. Womens Health (Lond). 2022 Jan-Dec;18:17455057221087865.

Mitchell KB, Johnson HM. Breast Pathology That Contributes to Dysfunction of Human Lactation: a Spotlight on Nipple Blebs. J Mammary Gland Biol Neoplasia. 2020;25(2):79-83.

O’Hara, M. A. Bleb histology reveals inflammatory infiltrate that regresses with topical steroids: A case series. Breastfeeding Medicine. 2012

Over-the-counter medication

NHS Specialist Pharmacy Service – UK Drugs In Lactation Advisory Service

Using paracetamol during breastfeeding, published November 2023

Using NSAIDS during breastfeeding, published February 2024

Other websites

Academy of Breastfeeding Medicine Clinical Protocol #36:The Mastitis Spectrum, 2022. https://www.bfmed.org/assets/ABM%20Protocol%20%2336.pdf

Books
The Art Of Breastfeeding. LLLI, London: Pinter & Martin, 2024

Breastfeeding Answers: a guide for helping families. Mohrbacher, N, 2020.

This information is available to buy as a printed booklet from our shop.