Mastitis is among the most common reasons women stop breastfeeding before they intended to. The combination of severe breast pain, fever, and feeling unwell while continuing to feed and care for a baby is genuinely difficult. Knowing what the condition is, that continuing to feed is part of the treatment rather than something to avoid, and when to seek medical help promptly, makes a significant difference to outcomes.
This article covers the spectrum from blocked duct through mastitis to the more serious breast abscess, including when each needs treatment and what that treatment involves.
Healthbooq (healthbooq.com) covers breastfeeding challenges through the first year, including conditions that are common but not always well managed.
Blocked Ducts
A blocked milk duct occurs when milk flow in one part of the breast is obstructed. The area may feel lumpy, tender, or hard. There is usually no systemic upset (no fever, no flu-like symptoms). The nipple may occasionally have a white spot on it (a milk bleb), which is the blocked duct opening at the surface.
Treatment involves increasing frequency of feeding from the affected breast, applying warm compresses before feeding, and massaging gently from the blocked area toward the nipple during feeding. Different feeding positions (where the baby's chin points toward the blocked area) can help drain that segment.
A blocked duct that is not resolving within a few days, or that is accompanied by fever, has likely progressed to mastitis.
Mastitis
Mastitis is inflammation of the breast tissue. It may be non-infective (inflammatory mastitis, caused by milk engorgement and stasis) or infective (bacterial mastitis, caused by Staphylococcus aureus in most cases). Clinically these can be difficult to distinguish, as both produce similar symptoms.
Symptoms include a hard, red, hot, painful area of the breast, usually wedge-shaped, following the segment of a milk duct. Systemic symptoms, fever, chills, myalgia, and feeling flu-like, develop quickly and are often the feature that brings the woman to a GP.
The critical mistake many women and some healthcare providers make is stopping breastfeeding from the affected breast. This is counterproductive: it allows milk to stagnate and worsens the condition. Continuing to feed (or express) from the affected breast as frequently as possible is part of treatment.
Antibiotics should be started promptly when systemic symptoms are present. Flucloxacillin 500mg four times a day for ten days is the usual first-line antibiotic in the UK. Erythromycin or clarithromycin are used if the woman is penicillin-allergic. Both are compatible with breastfeeding.
Pain relief with paracetamol and ibuprofen, rest, and adequate hydration are the supportive measures.
Symptoms should begin to improve within 24 to 48 hours of starting antibiotics. If they are not improving, or if a fluctuant lump develops, a breast abscess should be suspected.
Breast Abscess
A breast abscess is a collection of pus within the breast tissue, usually resulting from mastitis that has not resolved. The area develops a fluctuant swelling (soft and moveable under the finger, like a fluid-filled cyst). An ultrasound scan can confirm the diagnosis.
Treatment requires drainage of the abscess, either by aspiration (a needle inserted under ultrasound guidance, which can be repeated) or by surgical incision. Both are performed under local anaesthesia. Aspiration is preferable where possible as it allows continued breastfeeding.
Antibiotics continue alongside drainage. The choice of antibiotic may change depending on culture results from the pus.
Breastfeeding from the affected breast can usually be continued or resumed as soon as drainage has made it comfortable to do so.
Preventing Recurrence
Mastitis tends to recur in women who have had it once. Attention to latch and feeding position (poor latch leads to incomplete drainage), avoiding prolonged gaps between feeds or expressing, and identifying and addressing any source of nipple trauma (which allows bacteria to enter) are all relevant.
A breastfeeding specialist (IBCLC, infant feeding advisor) can assess latch and feeding technique and identify any structural reasons for poor drainage.
Lecithin supplements are sometimes recommended by lactation consultants for women prone to recurrent blocked ducts; the evidence is limited but it is safe and some women find it helpful.
When to Seek Help
See a GP or contact 111 for any breast pain with fever. If there is a history of mastitis and a fluctuant lump develops, this requires prompt assessment: aspiration should be arranged within 24 hours rather than waiting to see if it improves. An untreated abscess can rupture and requires more extensive surgical treatment.
National Breastfeeding Helpline (0300 100 0212) and La Leche League are available for breastfeeding support and can help with positioning and latch advice.
Key Takeaways
Mastitis is inflammation of the breast tissue that may or may not involve bacterial infection. It presents with a red, hot, painful area of the breast, often with flu-like symptoms including fever. Treatment involves continuing to breastfeed or express from the affected breast (stopping worsens the condition), antibiotics (usually flucloxacillin) when infection is present, and rest and analgesia. Mastitis that is not improving after 24 to 48 hours of antibiotics, or a fluctuant lump, may indicate a breast abscess, which requires drainage. A blocked duct (without systemic symptoms) precedes mastitis and can often be resolved with increased feeding frequency, breast massage, and warmth.
