Lactational Mastitis: Symptoms, Causes, and Treatment in the UK

Lactational mastitis is a condition where breast tissue becomes painful and inflamed, most common in women who are breastfeeding. In the UK, it is estimated that up to 1 in 10 breastfeeding mothers will experience mastitis, typically within the first three months after birth.

While the inflammation is often caused by milk stasis (where milk remains in the breast tissue rather than being drained), it can lead to a bacterial infection requiring medical intervention. According to NHS guidance, mastitis is not always an infection, but if left untreated, it can develop into a breast abscess, which may require surgical drainage.

Physical Breast Changes

The hallmark of mastitis is a wedge-shaped, red patch on the breast that feels hot to the touch and tender. You may also notice:

• A hard lump or area of engorgement that does not soften after feeding.
• Generalised swelling of the breast tissue (oedema).
• A burning pain that may be continuous or occur only during breastfeeding.
• Nipple discharge that may contain streaks of blood.

Systemic 'Flu-like' Symptoms

Many women feel significantly unwell before they even notice the red patch. These systemic symptoms include a high temperature (fever) of 38C or above, chills, aching muscles, and profound fatigue. If you feel as though you are coming down with the flu while breastfeeding, it is essential to check your breasts for signs of inflammation.

The primary cause of mastitis is milk stasis. This occurs when milk stays in the breast ducts rather than being removed through feeding or pumping. This stagnant milk can leak into the surrounding breast tissue, causing an inflammatory response.

Common triggers for milk stasis in UK patients include:

• Poor attachment: If the baby is not latching correctly, the breast may not be emptied efficiently.
• Infrequent feeds: Skipping feeds or a baby suddenly sleeping for longer periods.
• Pressure on the breast: Tight bras, seatbelts, or sleeping on your front can restrict milk flow.
• Oversupply: Producing more milk than the baby requires.

If bacteria (usually Staphylococcus aureus) enter through a cracked nipple or via the milk ducts, the inflammation can progress to a bacterial infection.

NICE clinical knowledge summaries suggest a 'wait and watch' approach for the first 12 to 24 hours if symptoms are mild. During this window, you should focus on the 'ABC' of mastitis care:

A: Always keep feeding

It is a common misconception that you should stop breastfeeding from the affected side. Continued feeding is the most effective way to clear the blockage. The milk is perfectly safe for your baby, as any bacteria will be destroyed by the baby's digestive system.

B: Better drainage

Ensure the baby is well-latched. You may want to contact a local breastfeeding support group or health visitor. Try 'dangle feeding' (leaning over the baby) to let gravity assist milk flow. Gently massage the lump toward the nipple during a feed.

C: Comfort measures

Applying a warm, damp cloth or taking a warm shower before a feed can help the milk flow. After a feed, a cold compress can help reduce swelling. For pain relief, paracetamol or ibuprofen are considered safe during breastfeeding and can help manage fever.

If your symptoms do not improve within 24 hours of improving your breastfeeding technique, or if you feel rapidly worse, you should speak to a GP online or in person. An online GP can assess your symptoms via video consultation and determine if you require prescription medication.

Under NICE guidelines, antibiotics are usually prescribed if:

• Self-care measures have not worked after 24 hours.
• Symptoms are severe from the outset.
• There is a visible nipple fissure (crack) which likely introduced a bacterial infection.

In the UK, the first-line antibiotic is usually flucloxacillin for 10 to 14 days. If you are allergic to penicillin, alternatives like erythromycin are used. Completing the full course is vital to prevent the infection from returning or developing into an abscess.

Once you have had mastitis, you are at a higher risk of it recurring. To prevent this:

• Check your baby’s latch frequently with a midwife or health visitor.
• Avoid wearing underwired or overly tight-fitting bras.
• Feed on demand and try to ensure the breast is soft after a feed.
• If you feel a small lump developing, prioritise rest and frequent feeding immediately to 'flush out' the blockage before it becomes mastitis.