Breast abscess !
A breast abscess is a pocket of pus in the breast, usually a complication of mastitis during breastfeeding or of inflammation behind the nipple.
Updated 2026-10-29
Structures involved
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Microorganisms that cause it
In the clinical exam
In physiology
Why it happens
- Outcomes of acute inflammation: resolution, abscess, scar or chronic inflammation
- Breast: ducts, lobules and changes with life stage
What it is
A localised collection of pus in the breast, usually as a complication of lactational mastitis or, outside lactation, of periductal inflammation behind the nipple.
Who gets it
Develops in a small fraction of women with lactational mastitis. Non-lactational abscesses near the areola affect mainly young to middle-aged women who smoke and tend to recur.
Causes
- Complication of lactational mastitis
- Periductal mastitis and duct ectasia (non-lactational, subareolar)
- Staphylococcus aureus, including methicillin-resistant strains; mixed and anaerobic bacteria in non-lactational abscesses
- Infected cysts or skin infections
Risk factors
- Mastitis that is delayed or inadequately treated
- Abrupt cessation of breastfeeding
- Smoking (subareolar abscess)
- Diabetes and obesity
- Nipple piercing
- Previous abscess
Pathophysiology
Infection that is not cleared leads to tissue necrosis, and the body walls off the pus in a cavity. Antibiotics penetrate the cavity poorly, so drainage is needed. In subareolar abscesses, blocked and inflamed ducts behind the nipple can form a fistula to the skin.
Classification
- Lactational (usually peripheral)
- Non-lactational (subareolar or peripheral)
- Single or multiloculated
Symptoms and signs
- Painful, swollen, red lump in the breast
- Fluctuance (may be absent in deep abscesses)
- Fever and malaise
- Skin thinning or spontaneous drainage of pus
- Nipple retraction in subareolar abscess
Diagnosis
- Clinical
- A painful, red, fluctuant lump, often after mastitis.
- Tests
- Culture of the drained pus to guide antibiotics; blood tests if systemically unwell; tissue sampling of the wall when cancer is a concern.
- Imaging
- Ultrasound confirms the collection, measures it and guides drainage; mammography after recovery in older women or when cancer must be excluded.
Differential diagnosis
- Mastitis without abscess
- Galactocele
- Inflammatory breast cancer
- Infected cyst
- Idiopathic granulomatous mastitis
Goal of treatment
Drain the pus, eradicate infection, allow breastfeeding to continue when possible and prevent recurrence, while excluding cancer.
Treatment
- Procedure
- Ultrasound-guided needle aspiration, often repeated, or placement of a small drain; first-line for most abscesses.
- Medical
- Antibiotics active against Staphylococcus aureus, adjusted to culture; broader cover for non-lactational abscesses.
- Surgical
- Surgical incision and drainage for large or multiloculated abscesses, failed aspiration or necrotic skin; excision of the diseased ducts for recurrent subareolar abscess.
- Conservative
- Analgesia and continued breastfeeding or expressing, at least from the unaffected breast; the affected side depends on the drainage site.
- Lifestyle
- Smoking cessation in non-lactational abscess, which lowers recurrence.
Complications
- Recurrence
- Mammary duct fistula
- Milk fistula after drainage
- Scarring and breast deformity
- Sepsis
Prognosis
Good with drainage and antibiotics; lactational abscesses usually heal without recurrence. Subareolar abscesses in smokers recur more often and may need duct surgery.
Prevention
- Early and complete treatment of mastitis with continued milk removal
- Avoiding sudden weaning
- Not smoking
Test yourself
Think of the answer, then tap the question to see it.
What is the first-line treatment of a breast abscess?
Ultrasound-guided needle aspiration or catheter drainage, plus antibiotics active against Staphylococcus aureus.
Why are antibiotics alone usually not enough for a breast abscess?
They penetrate the walled-off pus poorly, so the collection must be drained.
Which habit is strongly linked to non-lactational subareolar abscesses?
Smoking, which is associated with periductal mastitis and recurrence.
When should cancer be excluded in a breast abscess?
In non-lactating or older women, or when the abscess does not resolve or recurs.
Related conditions
Educational information, not medical advice. For any symptom, see a health professional.
Sources: Breast Abscess (StatPearls (NCBI Bookshelf), 2026).
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Representative model, for educational purposes only.