Topics

Breast Disease

Overview and approach

Lactational breast problems form a spectrum from a blocked duct to mastitis to abscess, with inflammatory breast cancer as an important mimic. Condition notes (with images) are below. Mastitis is inflammation of the breast, usually in someone breastfeeding; if not dealt with early, skin bacteria can get into the milk and cause infection (1).

  • Mastitis causes flu-like symptoms with breast redness, pain and swelling (1).
  • Risk factors: poor attachment (e.g. tongue tie), nipple damage, engorgement, long gaps between feeds, stopping breastfeeding too quickly, tight bra or clothing, fatigue (1).
Plugged/Clogged duct

An area of obstructed milk flow due to inadequate drainage of a milk duct, which can be caused by milk stasis and poor breastfeeding techniques and habits.
Baby can also be at fault.
Can present with a lump, tenderness, swelling, pain + discomfort while nursing and decreased supply. Distinguished from mastitis clinically due to lack of systemic symptoms.
Treatment of a plugged duct is important to prevent mastitis.

Breast diagram comparing a normal and a clogged milk duct
Blocked (plugged) milk duct compared with a normal duct Image: Hariadhi · CC BY-SA 4.0
Lactational mastitis

Condition in which a woman’s breast becomes painful, swollen and red, and can be
associated with a tender, firm lump and systemic flu-like symptoms.
Typically caused by prolonged engorgement or poor drainage (due to milk duct blockage,
infrequent feedings, rapid cessation, maternal stress etc.).

Affects approximately 20% of women in the first 6 months of breastfeeding, most
common within the first 6 weeks.
Risk factors include breastfeeding during puerperal period, milk stasis, previous mastitis,
maternal fatigue, primiparity, age > 30 and gestational age >= 41 weeks.
Preventative measures involve promoting good breastfeeding techniques/habits,
encouraging breast drainage and preventing nipple damage.

Breast abscess

Involves the localised collection of inflammatory exudate (pus) within the breast, can develop after mastitis or galactocele.
Clinically described as a “tender fluctuant area” (wave-like).
Reports indicate 3 - 14% of lactating women with mastitis will develop a breast abscess.
Treatment can involve needle aspiration or surgical drainage (depending on skin integrity) as well as antibiotics.
Not necessarily a contraindication for breastfeeding, milk drainage can help relieve symptoms

Galactocele

Cyst formed by milk retention in the mammary gland, it is the most common benign breast lesion in lactating women.
Typically painless, firm, milk-filled cyst in the retroareolar region.
Differentiated from other pathologies through USS as well as aspiration of a milky fluid (also therapeutic).
Can go on to form an abscess (everything seems to be a circle)

Inflammatory Breast Cancer

Rare, aggressive breast cancer which appears with similar clinical symptoms and signs as mastitis. Average age of diagnosis is younger than most locally advanced breast cancers (mid-to-late 50s compared to mid-to-late 60s) but still therefore typically occurs in post-menopausal women.
Tends to present with skin thickening, oedema, erythema, peau d’orange appearance and palpable axillary lymphadenopathy.
Should be considered if mastitis is not responsive to treatment, or if there are clinical, sonographic or aspiration-based indications

Breast diagram showing sites of lactational and subareolar abscesses
Sites of breast abscess, including lactational abscess Image: Hariadhi · CC BY-SA 4.0
Management and follow-up

Start treatment as soon as a painful, hard or red area is noticed (1).

  • Keep feeding or expressing from the affected breast (milk is safe for the baby); feed frequently, check positioning and attachment, gently express if still full (1).
  • Warm the breast just before feeds to help let-down; cold packs between feeds; ibuprofen or paracetamol (1).
  • Review within 12-24 hours if not improving or earlier if unwell; antibiotics if not improving quickly.
  • Breast abscess: needle aspiration or surgical drainage plus antibiotics; untreated mastitis can progress to abscess (1).
Red flags and clinical pearls

Mastitis that does not respond to treatment, or recurs in the same area, needs imaging and consideration of inflammatory breast cancer (skin thickening, oedema, peau d'orange, axillary nodes). Systemic toxicity or fluctuant lump suggests abscess (1).

References
  1. Healthdirect: Mastitis

Last updated from Sen’s notes on 9 October 2026.