Acute mastitis is usually associated with lactation and is frequently due to Staphylococcus aureus. It should be distinguished from simple “congestive mastitis” (breast engorgement).

If systemic symptoms develop, early treatment with antibiotics is important to prevent abscess formation.

Epidemiology

Lactation related mastitis is extremely common, with incidence ranging from 10-30 % of lactating women.

It is most common in first few weeks and nearly all cases occur within first 3 months, post delivery – cases may occur as long as the woman is breast-feeding.

Pathophysiology

Organism:

The most common infecting organism will be Staphylococcus aureus.

Precipitating factors:

The major precipitating factors include:

  1. Milk stasis from any cause:
    • Poor infant positioning
    • Poor infant feeding technique:
      • Too rapid weaning
      • Missed feeds
    • Tight constricting bra leading to overfilling of breasts, poor drainage and blocked ducts.
  2. Nipple trauma

Clinical assessment

Assess for:

  1. Systemic symptoms:
    • Fever
    • Constitutional symptoms
  2. Spreading cellulitis
    • Localised pain and swelling
    • Tender, red, warm cellulitic regions on the breast
    • There may be some associated axillary lymphadenopathy
  3. Masses:
    • A tender mass suggests an underlying abscess.

Investigations

In mild, uncomplicated cases, no investigations are usually required.

In more severe cases or when an underlying abscess is suspected the following may be considered:

Blood tests

  1. FBE
  2. CRP
  3. U&Es/ glucose
  4. Blood cultures should be considered if the temperature is > 38.5 C

Ultrasound

  • This is important if an underlying abscess is suspected.
  • If symptoms are severe or cellulitis is extensive, then an ultrasound should be done to rule out a clinically inapparent deep seated abscess.

Swabs of purulent discharge

Microscopy and Culture and sensitivity testing of any purulent material expressed.

Breast milk culture and sensitivity:

It is recommended to always

It is recommended to always send a milk sample for MC&S. Collect a hand-expressed mid-stream clean catch sample into a sterile container.

Management

Principles of management include:

1.         Milk expression and infant feeding:

  • Suckling or milk expression (manual or pump) from the infected breast should be continued and is safe.
  • In the absence of systemic symptoms in early mastitis, and without purulent discharge, increased feeding on the affected side and gentle expression may prevent progression.
  • Techniques to enhance enhancing breast milk drainage include:
    • Physiological methods (e.g. expressing, massage and breastfeeding)
    • Ensure correct positioning and attachment and frequent and effective milk removal
    • Apply warmth to assist with let-down reflex and therefore milk flow and breast drainage
    • Apply cold pack after feeds to reduce pain and oedema
    • Avoid restrictive clothing/bra

      If the baby is unable to feed directly from the affected breast, the breast should still be kept well drained by frequent and effective expressing until the mother is able to resume breastfeeding from that breast.

2.         Ensure adequate maternal hydration

3.         Analgesia:

  • Non-pharmacological:
    • Locally applied warm packs immediately prior to breastfeeding may assist milk flow. 2
    • Locally applied cool packs may give some symptomatic relief following breast feeds. 2
  • Pharmacological:
    • Simple oral analgesics, that are safe in breastfeeding include
      • Paracetamol
      • Non-steroidal anti-inflammatory drugs (NSAIDs)

4.         Antibiotics:

Antibiotics will be indicated for:

  • Cellulitis
  • Development of systemic symptoms, such as fever
  • Suspicion of (or actual) abscess formation

Options include:

  • Flucloxacillin 500 mg orally, 6-hourly for 10 days. 
  • Cefalexin 500mg orally, 6 hourly for 10 days (for non-immediate hypersensitivity to penicillin use)
  • Clindamycin 450mg orally, 8 hourly for 10 days (for immediate hypersensitivity to penicillin use)

If severe cellulitis has developed, antibiotics should initially be given IV. IV antibiotics should be continued for at least 48 hours or until substantial clinical improvement is seen.

See latest Antibiotic Therapeutic Guidelines for full prescribing details.

Failure of symptoms to improve after 2 to 3 days suggests other pathogens, or an abscess requiring review, surgical drainage and bacteriological examination of the pus.

Disposition

Most cases can be managed as an outpatient, but hospital admission may be required for:

  • Severe systemic symptoms
  • Spreading cellulitis not responding to oral antibiotics
  • Abscess formation
  • Significant associated co-morbidities
  • Maternal anxiety/ inability to cope with her baby

Referrals:

  • Specialist Nursing lactation consultant .
  • Women with a breast abscess need to be referred without delay to a breast surgeon.

References

FOAMed

Publications

  • Antibiotic Expert Groups. Therapeutic guidelines: Antibiotic. Version 16. Melbourne: Therapeutic Guidelines Limited; 2019.
  • Walker M. Breastfeeding management for the clinician: Using the evidence. 4th ed. Boston: Jones and Bartlett; 2017.
  • Therapetuic guidelines. Mastitis. Therapeutic guidelines. 2019 April.
  • Nastri CO, Ferriani RA, Rocha IA, Martins WP. Ovarian hyperstimulation syndrome: pathophysiology and prevention. J Assist Reprod Genet. 2010 Feb;27(2-3):121-8.

Fellowship Notes

Dr Jessica Hiller LITFL Author

Doctor at King Edward Memorial Hospital in Western Australia. Graduated from Curtin University in 2023 with a Bachelor of Medicine, Bachelor of Surgery. I am passionate about Obstetrics and Gynaecology, with a special interest in rural health care.

Physician in training. German translator and lover of medical history.

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.