How does a blocked duct differ from mastitis and a breast abscess?
They are not three separate illnesses but successive stages of one process. The Academy of Breastfeeding Medicine (ABM) describes them as a spectrum: from narrowing of the small milk ducts (commonly called a blocked duct), through inflammation without infection and bacterial mastitis, to an abscess. WHO defines mastitis as inflammation of the breast that may or may not be accompanied by infection.
Engorgement in the first days after birth is a separate situation and affects both breasts. How to deal with it is covered in our article on engorgement. Here we focus on problems that usually affect one area of one breast.
| Blocked duct (narrowed ducts) | Mastitis | Abscess | |
|---|---|---|---|
| What it looks like | A tender, hardened spot in one breast, sometimes slightly red | A hot, painful, swollen and red area, often wedge-shaped; on dark skin the redness may be harder to see | A very painful, clearly defined lump with red, warm skin; sometimes fluid can be felt |
| How you feel | Usually well, no fever | Often a fever, chills and flu-like aches; in two studies cited by WHO, one third to one half of women had local signs only | There may be a fever, but not always |
| Do you need a doctor | Usually not if it eases; yes if the lump persists or a fever develops | Yes, if there is no improvement after 12-24 hours of home care or you feel worse | Yes: the pus has to be removed, and antibiotics alone usually are not enough |
According to ABM, a single duct cannot be blocked by a milk “plug”, because the ducts in the breast form a dense network. A lump is therefore usually swelling and inflammation around the small ducts, not something that can be squeezed out. WHO uses the older term “blocked duct” and describes it as localised milk stasis in part of the breast.
How common is mastitis and when does it appear?
WHO points out that studies vary and that there are no large prospective ones. It reports that mastitis affects from a few percent up to 33% of breastfeeding women, but usually under 10%, with the higher figures coming from selected groups. It is most common in the second and third week after birth. Most reports indicate that 74-95% of cases occur in the first 12 weeks.
Mastitis can, however, happen at any stage of breastfeeding, including in the second year. According to ABM, an abscess develops in about 3-11% of women with acute mastitis.
What are the symptoms of mastitis?
The NHS describes symptoms that usually affect one breast and can come on quickly:
- a swollen, hot, painful area of the breast, sometimes red (on black or brown skin the redness is harder to see)
- a wedge-shaped lump or a hard area
- burning pain, either constant or only during feeds
- nipple discharge, whitish or streaked with blood
- flu-like symptoms: aches, a high temperature or feeling hot and shivery, tiredness
According to ABM, pain and redness in the morning after a long sleep are more often fullness and swelling than infection, because infection does not develop within a few hours. Hormone changes after birth can also cause hot flushes and sweating that are easy to mistake for a fever. If in doubt, take your temperature.
What causes mastitis and is it contagious?
The sources do not agree on a single cause. The NHS lists a build-up of milk, which is common in breastfeeding women, and risk factors: smoking, damage to the nipple (for example from a piercing or eczema), breast implants, a weakened immune system (for example in diabetes), and shaving or plucking the hairs around the nipples. WHO points to ineffective emptying of the breast because of poor feeding technique.
ABM stresses that the link with milk stasis is only a hypothesis, and that oversupply of milk (hyperlactation), disruption of the breast's microbiome and frequent pumping play an important role. Among circumstances that may contribute, it also mentions caesarean birth, exclusively pumping and using nipple shields. According to ABM there is no evidence that particular foods cause mastitis, and poor hygiene is not a cause.
Mastitis is not contagious and does not endanger the baby. You do not need to sterilise your pump or toys; ordinary handwashing and cleaning pump parts after use is enough.
What to do at home for a blocked duct or mastitis?
The NHS, WHO and ABM agree that the basis is effective milk removal by the baby and reducing inflammation, not “squeezing out” the breast. In practice:
- Feed on demand, as often and as long as your baby wants. Do not add extra feeds or pumping “by force”. ABM warns that emptying the breast completely drives up milk production and worsens inflammation.
- If feeding hurts too much or your baby will not suck on that breast, hand express only as much as your baby normally takes. The NHS advises not to express more than your baby needs.
- Ask a midwife or lactation consultant to check your baby's attachment. According to WHO this is the most important part of treatment, because without better milk removal symptoms return even with antibiotics.
- Apply a cold compress to the sore area. The NHS suggests 10 minutes every hour, and ABM pairs cold with anti-inflammatory medicine as the basis for easing swelling.
- For pain or a fever you can take paracetamol or ibuprofen. The NHS notes that you should not take aspirin. According to WHO, ibuprofen is the most effective because it also reduces inflammation.
- Rest, ideally in bed with your baby because this makes frequent feeding easier, drink enough fluids and wear a comfortable bra that does not press.
- Use only gentle pressure. The NHS advises against firm pressure, oils, soaking the breast and creams.
The sources differ on two details. On warmth, WHO and some Polish experts recommend warm compresses before feeding, while ABM says heat widens blood vessels and may worsen swelling, although some women find it soothing. If warmth helps you, use it briefly before a feed and cold after. The second difference is which breast to start with: the NHS suggests starting with the sore one, while ABM advises against stimulating it too much and describes a case in which feeding started from the less full breast. When swelling is so severe that no milk can be expressed from the sore breast, ABM allows feeding from the other breast only until the swelling goes down.
Can you keep breastfeeding with mastitis, and is the milk safe?
Yes. WHO states that stopping breastfeeding during mastitis does not help the mother recover and may make her condition worse. Studies described by WHO show that feeding from an infected breast is generally safe for the baby, even when Staphylococcus aureus is present in the milk. The only exception is when the mother has HIV. ABM adds that bacterial mastitis does not endanger the baby and does not require a break from breastfeeding.
Polish experts from Medycyna Praktyczna also stress that mastitis is not a contraindication to breastfeeding. There is no need to express and throw away the milk. WHO notes that milk from an inflamed breast can taste saltier, usually for about a week, so your baby may be fussy at that breast for a while. The NHS says that with antibiotics a very small amount of the drug may pass into the milk and make the baby irritable and restless, but this poses no risk.
When do you need antibiotics for mastitis?
Not every case of mastitis needs antibiotics, but the decision is the doctor's, not yours. ABM recommends keeping antibiotics for bacterial mastitis. It cites a Swedish study in which most women with inflammation without infection recovered without antibiotics or other interventions, thanks to symptom relief and regular contact with a clinician. On the other hand, Medycyna Praktyczna notes that in practice most women with mastitis are given an antibiotic, and that how well antibiotics work in this condition is debated in the scientific literature.
| Source | When to take antibiotics or see a doctor |
|---|---|
| NHS | No improvement after 12-24 hours of home care. If a doctor prescribed antibiotics, no improvement 48 hours after starting them. |
| WHO | Severe symptoms from the start, a visible nipple crack, or no improvement after 12-24 hours of better milk removal. |
| ABM | General symptoms such as fever and a fast heart rate lasting longer than 24 hours, or no response to conservative treatment. |
| Medycyna Praktyczna (Dr Nehring-Gugulska) | No improvement within 24 hours, the mother getting worse, or damage to the nipple at the same time. |
If antibiotics are needed, WHO, ABM and Medycyna Praktyczna all give 10-14 days. WHO notes that shorter courses are linked to more relapses. As first-choice drugs, ABM lists flucloxacillin or dicloxacillin and cefalexin, and Medycyna Praktyczna lists cloxacillin or cephalosporins. Ask your doctor for a drug that is compatible with breastfeeding, because most can be used without stopping feeds.
ABM and WHO advise testing a milk culture when there is no improvement after 48 hours of antibiotics, when mastitis keeps coming back, or in severe cases. It helps choose a drug when the bacteria are resistant.
What is a breast abscess and how do you recognise it?
An abscess is a localised collection of pus in the breast, a complication of mastitis that was not treated in time. WHO describes it as a very painful, swollen lump with red, warm skin, and ABM adds that pain and redness keep growing and that fluid can often be felt in a well-defined area. A fever may or may not appear.
An abscess needs its pus removed. According to WHO, treating it with antibiotics alone, without draining the abscess, is usually not enough, because the abscess wall shields the bacteria from the drug. The diagnosis can be confirmed with an ultrasound scan. ABM describes needle aspiration of the pus, often under ultrasound guidance, or placing a drain, and antibiotics are usually given as well. After the procedure you can feed from that breast if it is possible. The NHS confirms that you can keep breastfeeding during abscess treatment.
What to avoid with a blocked duct or mastitis?
- Strong, deep massage and “working out” hard spots. ABM considers it a main risk factor for an abscess, because it damages small blood vessels and worsens swelling.
- Squeezing or pushing out a supposed “plug”. According to ABM it does not work and damages tissue.
- Pumping “until empty” and extra pumping sessions in the hope of clearing the blockage. This increases milk production.
- Massagers, vibrators and electric toothbrushes held against the breast.
- Castor oil, salt compresses, soaking the breast and ointments, and for pain also aspirin.
- Stopping feeding suddenly and skipping feeds, which according to the NHS can make symptoms worse and lead to an abscess.
- Piercing the white spot on the nipple. ABM advises against “unroofing” it because it damages tissue and narrows the duct further.
- Nipple shields without a clear need. According to ABM there is no evidence of their effectiveness or safety.
What to do if mastitis keeps coming back?
The NHS notes that recurring mastitis often points to a problem with attachment, so ask a midwife or lactation consultant to watch a feed. For recurrences ABM advises not treating blindly but examining the breast and testing a milk culture, checking for oversupply, unnecessary pumping or aggressive massage, and finishing the treatment of the previous episode.
If the inflammation keeps returning in the same place, ABM recommends imaging to rule out a lesion in the breast. Symptoms such as spreading redness, drawing in of the skin or an orange-peel texture need urgent review by a breast surgeon and an oncologist. This does not mean mastitis is a cancer, but changes that do not respond to treatment need to be checked.
Among factors you can influence, the NHS names smoking and nipple damage, and ABM names oversupply of milk and unnecessary pumping. In practice it helps to feed on demand without skipping feeds, wear a comfortable bra and act quickly at the first symptoms.
When should you call a midwife and when a doctor?
Contact a midwife or lactation consultant straight away at the first signs of a blocked duct: a painful lump, trouble getting your baby to attach, sore nipples or repeated problems. Improving the attachment most often solves the problem and prevents it coming back.
See a doctor the same day, or use out-of-hours care if you cannot reach one, if:
- you have a fever, chills and flu-like symptoms that do not ease after 12-24 hours of home care
- the red, hot, painful area of the breast is getting bigger
- a hard, very painful lump appears in the breast or pus comes from the nipple
- you feel worse and worse even though you are feeding and resting
- you have been on antibiotics for 48 hours and there is no improvement
- you are not breastfeeding but have symptoms of mastitis (the NHS advises seeing a doctor in this case)
Call an ambulance on 112 or go to the emergency department if symptoms are severe: you have a high fever with chills and a racing heart, you cannot drink or take medicine by mouth, or you are very weak. ABM notes that hospital admission may be needed with signs of severe sepsis and when a woman cannot take medicine and fluids by mouth. In that case mother and baby should stay together, and feeding on demand is still recommended.
You can get help with feeding problems free of charge from your POZ midwife (the primary care midwife in Poland's public health system). After birth she makes at least 4 patronage visits at home, the first within 48 hours (not counting weekends and public holidays) of the birth being reported, and her tasks include lactation consultations and support with feeding problems. If you need help sooner or a longer visit, on MyMidwife you will find midwives with lactation experience who will come to your home.
