Blocked Ducts and Mastitis: Symptoms, Treatment, and Prevention

Blocked ducts and mastitis are among the most common reasons women stop breastfeeding before they planned to. They can be very painful and, in the case of mastitis, genuinely make you feel quite unwell. But with prompt action most cases resolve without complications.

Here's what to look for, what to do, and when you need medical help.

Blocked Ducts

What Is a Blocked Duct?

Breast milk flows from the milk-producing lobules through a network of ducts to the nipple. When milk isn't adequately drained from one part of the breast, milk can pool and thicken, eventually blocking the duct. This is a blocked duct (also called a plugged duct).

What It Feels Like

• A hard, tender lump in the breast — often clearly defined, like a marble or small stone under the skin
• Localised discomfort or aching, sometimes quite intense
• The skin over the lump may be red and warm, but this is localised
• No flu-like symptoms (fever, chills, body aches) — if you have these, see mastitis below

What to Do

The treatment for a blocked duct is continued removal of milk, combined with gentle massage and warmth.

Keep feeding. Feed from the affected breast first at each feed, when your baby feeds most vigorously. The more milk is removed, the sooner the blockage clears.

Position the baby to drain the blocked area. Point your baby's chin toward the lump — the section of breast that drains toward the chin is where the most effective removal happens. This might mean unusual feeding positions (the football hold, or even leaning over your baby while they lie on a surface).

Warm compress before feeding. A warm (not hot) flannel or shower before feeding helps milk flow more freely. Don't apply ice — this reduces flow.

Gentle massage. Massage the lump toward the nipple during feeding or pumping. Gentle, firm pressure — not aggressive massage, which can cause bruising and inflammation.

Express if needed. If your baby won't feed on the affected side, express instead to keep milk flowing.

Most blocked ducts resolve within 24–48 hours of this treatment. If yours isn't improving or is getting worse, see your GP.

Mastitis

What Is Mastitis?

Mastitis is inflammation of the breast tissue, usually caused by milk stasis (milk pooling in the breast). It can be non-infective (inflammation without bacterial infection) or infective (with bacterial infection). You can't always tell which type you have from symptoms alone, but the treatment starting point is the same.

What It Feels Like

Mastitis looks like an inflamed, hot, red area of the breast, but it also makes you feel systemically unwell:

• Flu-like symptoms: Fever (often over 38°C), chills, aching muscles, fatigue, headache
• A wedge-shaped red, hot area of the breast (following the affected duct)
• Pain and tenderness in the affected area, often more severe than a blocked duct
• The red area may be hard and clearly demarcated

If you have a hot, red breast plus flu-like symptoms, this is likely mastitis and needs prompt treatment.

What to Do

Keep feeding. This is the most counterintuitive but most important instruction. Stopping feeding with mastitis slows recovery and increases the risk of complications. Feed frequently from the affected breast.

Contact your GP promptly. Mastitis may require antibiotics, and you shouldn't wait to see if it improves on its own once you have systemic symptoms. Most GPs will prescribe antibiotics over the phone for mastitis given clear symptom description.

If antibiotics are prescribed: Flucloxacillin or erythromycin are commonly prescribed and are safe to use while breastfeeding. Take the full course even if you feel better quickly.

Rest. Mastitis is an illness. You feel ill because your body is fighting inflammation. Rest as much as you can.

Pain relief. Ibuprofen is the first choice — it has both pain-relieving and anti-inflammatory effects. Paracetamol can be added. Both are safe while breastfeeding.

Heat and massage. Continue warm compresses and gentle massage toward the nipple before and during feeding.

When to Go to A&E or Call 111

Go urgently if:

• Symptoms are rapidly worsening despite treatment
• You develop a fluctuant (soft, fluid-filled) swelling within the red area — this can indicate an abscess
• Fever is very high and you feel extremely unwell
• You develop pus-like nipple discharge

A breast abscess is a serious complication that requires drainage by a specialist. It's uncommon with prompt mastitis treatment, but recognising it early matters.

Prevention

Common Causes of Blocked Ducts and Mastitis

• Irregular or missed feeds — weekends away, a baby suddenly sleeping longer, returning to work, or illness that reduces feeding
• Ineffective milk removal — a shallow latch, tongue tie, or baby who feeds inefficiently
• External pressure on the breast — an underwired bra pressing on a duct, carrying a bag that sits against the breast, sleeping on the front
• Sudden weaning — too rapid a reduction in feeding
• Cracked nipples — these can allow bacteria to enter the breast tissue

Prevention Strategies

• Feed responsively — don't delay or skip feeds
• Ensure good latch and effective milk transfer (get help if feeding is painful)
• Vary feeding positions to ensure different parts of the breast are drained
• Wear properly fitting, non-underwired bras or nursing bras during breastfeeding
• If you're going to miss a feed (night out, return to work), express to prevent engorgement
• Don't wean suddenly — reduce feeds gradually to allow supply to adjust

A Note on Lecithin

Sunflower lecithin is a food supplement sometimes recommended for women who have recurrent blocked ducts. The evidence is limited, but it is considered safe and some women find it helpful. It may help by changing the composition of milk, making it flow more freely. It's not a first-line treatment but is worth discussing with a lactation consultant if you have repeated episodes.