Breast abscess in breastfeeding: from mastitis to a collection of pus

The NHS describes a sequence. Breast engorgement is when the breasts become overly full, hard and painful. A blocked milk duct can follow if a segment is not drained properly, causing a small tender lump. If a blocked duct is not relieved it can lead to mastitis, an inflamed, hot, tender and swollen breast with flu-like symptoms, which can turn into an infection needing antibiotics. If mastitis is not treated or does not respond, it can lead to a breast abscess.

A Scottish guideline from NHS Dumfries and Galloway says this is a continuum from engorgement through to abscess, that mastitis occurs when milk is not drained effectively from part of the breast and becomes pressurised, and that abscesses can also occur without preceding mastitis symptoms.

The Dumfries and Galloway guideline describes an abscess as a well-defined, firm, extremely tender swelling, with or without redness or darker skin. The NHS mastitis symptoms that may come first include a swollen, hot and painful area (redness may be harder to see on black or brown skin), a wedge-shaped lump or hard area, a burning pain, and flu-like symptoms such as aches, a high temperature and tiredness.

The same guideline notes a fluid-filled sac may also be a galactocele, a harmless sac of milk, which is one reason a lump should be assessed rather than assumed. It also says that an infection that does not clear may, uncommonly, be a sign of inflammatory breast cancer and needs further investigation, which is why persistent problems should always be reviewed.

The NHS advises continuing to breastfeed when your baby wants, offering the affected side first while not letting the other breast get too full, checking positioning and attachment with a midwife, health visitor or breastfeeding specialist, hand expressing enough to relieve fullness (not more, as that increases supply), cold compresses, paracetamol or ibuprofen, rest and a supportive bra. It says not to take aspirin, apply firm pressure, stop breastfeeding suddenly or apply oils or creams. The Dumfries and Galloway guideline likewise says not to stop breastfeeding, not to add extra feeds or pumping sessions, to use ice wrapped in a cloth for 10-minute intervals rather than heat packs, and that ibuprofen and paracetamol are safe while breastfeeding if there are no contraindications.

The NHS says see a GP if mastitis symptoms do not get better 12 to 24 hours after treating at home, if they do not improve 48 hours after taking antibiotics, or if you get mastitis and are not breastfeeding. A GP will usually prescribe antibiotics if symptoms are not improving. The NHS says a very small amount of antibiotic may go into breast milk, with no risk to the baby, though it might make them irritable and restless.

NICE postnatal guidance tells midwives to advise women to seek medical advice if redness and swelling of the breasts persist for more than 24 hours despite self-management, which could indicate mastitis. The Scottish guideline says rarely mastitis can lead to sepsis and needs emergency admission, with babies kept with their mothers. If you feel very unwell, shivery, confused or breathless, call 999.

An abscess is typically managed by ultrasound-guided drainage or by incision and drainage under general anaesthetic, with same-day referral, according to the Dumfries and Galloway guideline. The NHS says an abscess may need a procedure to drain it. Antibiotics may accompany drainage at the clinician's discretion, and you should never start or stop antibiotics without advice. Milk culture may be considered in severe or recurrent cases, the guideline says.

The NHS says you can carry on breastfeeding while having treatment, and the Scottish guideline says mothers should be supported to have their babies with them if admitted. Ask the breast or surgical team how to feed or express comfortably around any dressing or drain. Pathways differ between hospitals and UK nations.

The NHS says that if you keep getting mastitis it might be due to positioning and attachment problems and to ask for help from a midwife, health visitor or breastfeeding specialist as soon as possible. It lists the National Breastfeeding Helpline for support. Mastitis can also be caused by smoking, nipple damage, a breast implant or a weakened immune system. NICE says postnatal contacts include asking about nipple and breast discomfort and symptoms of inflammation.