Mastitis is one of the leading reasons women stop breastfeeding earlier than they planned. Severe breast pain, a high fever, and feeling like you've been hit by a truck — all while continuing to feed and care for a baby — is genuinely difficult. The good news is that the management is well established. Knowing what mastitis actually is, that continuing to feed is part of the treatment (not something to avoid), and when to escalate to medical help makes a real difference to how this resolves.
This article covers the spectrum from blocked duct through mastitis to breast abscess: what each looks like, what to do, and when to get help fast.
Healthbooq (healthbooq.com) covers breastfeeding challenges across the first year, including conditions that are common but not always managed well.
Blocked Ducts
A blocked duct is what happens when milk flow in one segment of the breast slows or stops. You feel a tender lump or a hard lumpy area, often in one wedge of one breast. There's no fever, no flu-like aching — just a localised sore patch. Sometimes a tiny white spot appears on the nipple itself (a milk bleb), which is the duct opening blocked at the surface.
Treatment is mechanical:
- Feed more often from that breast. More drainage, less stagnation.
- Warmth before feeding — a warm flannel or a few minutes in the shower softens the area.
- Gentle massage during the feed, working from the lump toward the nipple.
- Position the baby with their chin pointing toward the lump. The chin is where the strongest drawing happens, so it preferentially drains that quadrant.
A blocked duct that hasn't budged after a couple of days, or that suddenly comes with fever, has likely tipped into mastitis.
Mastitis
Mastitis is inflammation of breast tissue. It may be non-infective (driven by milk stasis and the inflammatory response to it) or infective (most often Staphylococcus aureus). Clinically the two look similar enough that you can rarely tell them apart from the bedside.
The picture is fairly distinctive: a hard, red, hot, painful area of breast — usually wedge-shaped, following one duct system — accompanied by fast-onset systemic symptoms. Fever, chills, aching, feeling flu-like. Many women describe it as the moment they thought "something is properly wrong" and called the GP.
The most common — and damaging — mistake is to stop breastfeeding from the affected breast. This is the opposite of what's needed. Milk that doesn't come out makes everything worse. Continuing to feed (or to express, if the latch is too painful) from the affected breast is part of the treatment, not something to avoid.
When systemic symptoms are present, antibiotics should be started promptly. Flucloxacillin 500 mg four times a day for 10 days is the standard UK first-line. For penicillin allergy, erythromycin or clarithromycin are used; both are compatible with breastfeeding.
Pain relief — paracetamol and ibuprofen, alternating as needed — plus rest and good hydration round out the supportive care.
Symptoms should start to improve within 24–48 hours of starting antibiotics. If they don't, or if a soft fluctuant lump develops where the hard area used to be, suspect a breast abscess and get reassessed quickly.
Breast Abscess
A breast abscess is a walled-off collection of pus, usually a complication of mastitis that didn't fully resolve. It feels different from the original mastitis: instead of a hard wedge, there's a softer, fluid-filled lump that moves under the finger like a small water balloon. An ultrasound scan confirms it.
Treatment is drainage, either by needle aspiration under ultrasound guidance (often repeated over a few days) or by surgical incision. Both are done under local anaesthetic. Aspiration is generally preferred where it's an option — it's less disruptive, leaves a smaller mark, and allows breastfeeding to continue throughout.
Antibiotics carry on alongside drainage. The choice may be adjusted depending on what grows from the pus.
Breastfeeding from the affected side can usually continue or restart as soon as the area is comfortable enough.
Preventing Recurrence
If you've had mastitis once, you're more likely to get it again. The preventable side of this is mostly about effective drainage:
- Address the latch. A poor latch leaves segments under-drained, which is exactly the setup for the next blocked duct.
- Avoid long gaps between feeds or pumping sessions, especially in the early weeks.
- Treat any nipple damage early — cracks let bacteria in.
A breastfeeding specialist (IBCLC or NHS infant feeding advisor) can watch a feed and identify the structural reason behind repeated episodes — often it's something specific and fixable.
Lecithin supplements (a phospholipid that may keep milk fats less prone to clumping) are sometimes recommended for women with recurrent blocked ducts. Evidence is limited but the supplement is safe, and some women find it helps.
When to Seek Help
See a GP, or call 111 if out of hours, for any breast pain accompanied by fever. If you've had mastitis before and a soft fluctuant lump develops, treat that as urgent — aspiration should be arranged within 24 hours rather than waiting to see if it gets better. An untreated abscess can rupture and then needs more invasive surgical management.
National Breastfeeding Helpline (0300 100 0212) and La Leche League can provide breastfeeding support and help troubleshoot positioning and latch.
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.
