Puerperal mastitis

Definition

• Puerperal (lactational) mastitis is an inflammation of the lactating breast that usually manifests within the first 6 weeks after birth.

Classification

• Lactational mastitis is distinguished from non-lactational chronic inflammatory forms such as periductal and idiopathic granulomatous mastitis; breast abscess is a complication of both.

Aetiopathogenesis

Aetiology and risk factors

• It typically arises from milk stasis and bacterial infection through damaged skin; staphylococci are the commonest causative organisms.
• In the review, nipple damage was the risk factor most consistently associated with mastitis.

Clinical features

Picture

• Puerperal mastitis usually appears in the second to fourth week after birth.
• Clinically there is usually one-sided, often wedge-shaped redness with warmth, pain, fever above 38.5 °C and feeling unwell.
• The commonest organism is Staphylococcus aureus; the portal of entry is cracks in the nipple.
• On ultrasound you look for a hypoechoic, possibly septated collection indicating an abscess.

Milk stasis

• Typical are a localised, tender lump with redness and at most a slight rise in temperature.
• The difference from mastitis lies in the degree of systemic symptoms and in the fever.

Clinical features and complications

• Breast abscesses are very rare, occasionally caused by MRSA, and more frequent in smokers and women with higher body weight.

Diagnosis

Typical imaging findings

• Clinical finding: A sharply outlined, wedge-shaped area of redness runs from the periphery towards the nipple; the overlying skin is tense and warm. There is no retraction, no peau d orange and no palpable fluctuation.

• In unclear or non-lactational mastitis, imaging, histology and bacterial culture are used for evaluation.

Keep learning in the app

Further reading (selection)

1. StatPearls: Acute Mastitis (NCBI Bookshelf)
2. MSD Manual Professional Edition: Mastitis
3. J Hum Lact 2020: Incidence of and Risk Factors for Lactational Mastitis – systematic review (PMC, open access)
4. DocCheck Flexikon, Mastitis puerperalis
5. DocCheck Flexikon, Laktation

Cross-references