What if that red, painful breast isn’t an infection — and antibiotics aren’t needed?

Mastitis is now seen as a spectrum, often inflammatory rather than infective. Treating it as routine infection risks overprescribing and missing early, effective care.

Talking to Lactation medicine physician Dr Yvonne Le Fort we unpack the case of Kim, a well 26-year-old female, three months postpartum with a tender, erythematous breast, we cover:

When mastitis is inflammatory vs infective

What early management should prioritise

When antibiotics are actually needed

Red flags and when to escalate

Practical clinical pearls:

• Mastitis is a spectrum — it may be inflammatory and is not always due to infection.
• Initial management of lactational mastitis- includes pain relief, reducing breast oedema, and addressing hyperlactation.
• Milk culture – consider if symptoms persist despite antibiotics, or if mastitis is recurrent or prolonged.
• Antibiotics – not all cases need them. Use only for systemic symptoms or if no improvement after 24–48 hours. First-line: Flucloxacillin. If penicillin allergy: Clindamycin
• Breast abscess or mass – refer urgently for imaging ± surgical drainage.
• Non-lactational mastitis – usually infective; requires antibiotics and close follow-up. Refer early if cancer suspected.
• Inflammatory breast cancer can mimic mastitis — maintain a high index of suspicion.

Guest bio:

Dr Yvonne LeFort, a family medicine doctor trained in Canada, has practised breastfeeding medicine for over 20 years and runs a private breastfeeding clinic on Auckland’s North Shore.

She is a dual Fellow of RNZCGP and CCFP (Canada), an IBCLC, and a Fellow of the Academy of Breastfeeding Medicine (ABM). She serves on the board of the New Zealand Breastfeeding Alliance (NZBAA), supporting evidence-based breastfeeding education for all medical and health care colleagues.

Currently, she is a professional advisor to La Leche League New Zealand, a member of NZLCA, and the founder of a Breastfeeding Medicine RNZCGP Peer Review Group.

Yvonne has recently completed a Post Graduate Diploma in Digital Health from Otago University.

She has provided both formal and informal education for IBCLCs and medical colleagues, helping to upskill healthcare workers with the knowledge needed to provide best-practice care when consulting with breastfeeding dyads. She has presented nationally and internationally on a wide variety of topics.

Yvonne is the first author of the ABM’s Position Statement on Ankyloglossia and Breastfeeding Dyads (2021), a contributor to New Zealand Aotearoa National Guidance for the Assessment, Diagnosis and Surgical Treatment of Tongue-Tie in Breastfeeding Neonates, and a co-author of Complications and Misdiagnoses Associated with Infant Frenotomy: Results of a Healthcare Professional Survey (International Breastfeeding Journal, 2022), along with several other clinical protocols.

Resources:

https://www.redwhale.co.uk/content/the-mastitis-spectrum

https://www.bfmed.org/assets/ABM%20Protocol%20%2336.pdf

https://www.tewhatuora.govt.nz/for-the-health-sector/specific-life-stage-health-information/maternal-health/breastfeeding/breastfeeding-problems/mastitis-and-breast-abscesses/

https://tewhatakura.nz/guidelines