Mastitis

Definition/diagnostic criteria

Mastitis is an inflammatory condition of the breast tissue, often associated with lactation, but can also occur in non-lactating women. The condition can be classified into two main types: infectious (bacterial) mastitis and non-infectious mastitis. Infectious mastitis typically involves the presence of bacteria, commonly Staphylococcus aureus, whereas non-infectious mastitis may result from milk stasis or duct obstruction.

Epidemiology

Mastitis predominantly affects breastfeeding women, with an estimated incidence of around 10-20% in this population. It is most common in the first six weeks postpartum but can occur at any stage of lactation. Non-lactating mastitis is less common and can affect women of any age, particularly those with certain risk factors such as smoking, nipple piercings, or immunosuppression.

Diagnosis

Clinical features: Mastitis presents with a range of symptoms, including:

• Localised breast pain and tenderness
• Erythema and warmth over the affected area
• Swelling and hardness of the breast tissue
• Fever and flu-like symptoms (in infectious mastitis)
• Nipple discharge, which may be purulent in infectious cases

Investigations and typical abnormalities: Diagnosis is primarily clinical, based on history and physical examination. Key features include the abrupt onset of breast pain and systemic symptoms in lactating women. If infection is suspected, especially if there is no improvement with initial treatment, a breast milk sample may be cultured to identify the causative organism. Ultrasound may be used to rule out abscess formation or other complications if the presentation is atypical or if symptoms persist despite treatment.

Treatment

Treatment strategies for mastitis focus on symptom relief, continued breastfeeding, and addressing any underlying infection.

• Non-infectious mastitis: The primary approach includes effective milk removal through continued breastfeeding or expressing milk, ensuring proper breastfeeding techniques, and applying warm compresses to the affected area. Analgesics such as paracetamol or ibuprofen can be used for pain relief.
• Infectious mastitis: In addition to the above measures, antibiotic therapy is required. First-line antibiotics include flucloxacillin or erythromycin (for those allergic to penicillin). Antibiotics should be continued for at least 10-14 days to prevent recurrence. If an abscess is suspected or confirmed, surgical drainage or needle aspiration under ultrasound guidance may be necessary.

Prognosis

With appropriate treatment, the prognosis for mastitis is generally excellent. Most cases resolve within a few days to weeks. Early and effective management is crucial to prevent complications such as abscess formation, which may require more invasive interventions. Recurrent mastitis may necessitate further investigation to identify and address any underlying issues, such as improper breastfeeding techniques or underlying breast pathology.

For non-lactating women, addressing underlying risk factors is important to prevent recurrence. Chronic or recurrent mastitis may necessitate further evaluation, including imaging and possibly biopsy, to exclude malignancy.