Lactational Mastitis

Overview

Lactational mastitis is inflammation of breast tissue that occurs in people who are breastfeeding, often accompanied by infection. It typically causes a painful, red, swollen area of the breast along with fever and flu-like symptoms, and it usually affects one breast. Mastitis is most common in the first few weeks of breastfeeding but can happen at any point during nursing.

It often begins when milk builds up in part of the breast and is not effectively removed, sometimes from a blocked duct, missed feeds, or difficulty with latch. The trapped milk causes inflammation, and bacteria, which can enter through a cracked or sore nipple, may lead to infection. While mastitis can feel quite unwell and discouraging, it is common and usually improves with frequent milk removal, supportive measures, and, when needed, antibiotics. In most cases breastfeeding can and should continue, which actually helps the breast recover.

Symptoms

Symptoms usually come on over a short time and affect one area of one breast.

• A red, warm, swollen, and tender area of the breast, sometimes wedge-shaped
• Breast pain or a burning sensation, which may be worse during feeding
• A firm, painful lump or area of hardness in the breast
• Fever, chills, and flu-like aches and tiredness
• Feeling generally unwell

Mastitis can sometimes progress to a collection of pus (a breast abscess), which may feel like a tender, fluctuant lump. Worsening symptoms despite treatment, a persistent firm lump, or high fever should prompt medical review. Seek urgent care if you feel very unwell, have a very high fever, or notice spreading redness, as a more serious infection may need prompt treatment.

Causes

Mastitis develops when milk is not effectively removed from part of the breast and inflammation, and often infection, follows.

• Milk stasis: Milk that builds up and is not drained well, often from a blocked duct, infrequent or missed feeds, oversupply, or problems with latch and positioning.
• Bacterial infection: Bacteria can enter through a cracked, sore, or damaged nipple and grow in the trapped milk.
• Pressure on the breast: Tight clothing or bras and pressure from sleeping position can contribute to blocked ducts.

Anything that makes complete milk removal harder, such as a sudden change in feeding routine, stress, or fatigue, can increase the chance of mastitis.

Risk Factors

• Cracked or sore nipples
• Difficulty with latch or positioning
• Infrequent feeds, missed feeds, or sudden weaning
• An oversupply of milk or a previously blocked duct
• A previous episode of mastitis
• Tight bras or pressure on the breast
• Being very tired or run down, especially in the early weeks of breastfeeding

Diagnosis

Mastitis is usually diagnosed from the typical symptoms and a breast examination, without the need for special tests.

• History and examination: A doctor reviews symptoms and feeding patterns and examines the red, tender area of the breast.
• Ultrasound: May be used if an abscess is suspected or if symptoms do not improve, to look for a collection of pus.
• Milk or other testing: Occasionally used in recurrent or severe cases to identify the bacteria involved.

If a firm lump remains after the infection clears, further evaluation may be advised to be sure nothing else is present.

Treatment

The cornerstone of treatment is keeping milk flowing while supporting the body to recover. Most people can continue breastfeeding throughout.

• Continue feeding or expressing: Frequent, effective milk removal from the affected breast helps it drain and recover; breastfeeding is safe to continue.
• Comfort measures: Gentle support, rest, plenty of fluids, and a cool or warm compress as comfortable.
• Pain relief: Over-the-counter pain and anti-inflammatory medicines compatible with breastfeeding can ease pain and fever.
• Antibiotics: Prescribed when an infection is likely or symptoms do not improve within a day or so; it is important to complete the full course.
• Abscess care: If a pus collection forms, it may need to be drained with a needle or minor procedure.

Addressing the underlying cause, such as improving latch or feeding frequency, helps prevent it from coming back. A lactation consultant can be very helpful.

Prevention

• Breastfeed regularly and ensure the breast is well drained at feeds
• Get help with latch and positioning if feeding is painful or difficult
• Treat cracked or sore nipples promptly
• Avoid long gaps between feeds and wean gradually rather than suddenly
• Avoid tight bras and pressure on the breast
• Rest, stay hydrated, and look after yourself, especially in the early weeks

When to See a Doctor

Contact a doctor if you have a painful, red area of the breast with fever or flu-like symptoms, especially if it does not improve within about 24 hours of frequent milk removal and self-care. Seek prompt or urgent care if you:

• Feel very unwell or have a high or rising fever
• Notice spreading redness or a tender, fluctuant lump suggesting an abscess
• Have symptoms that worsen despite antibiotics
• Have a firm lump that remains after the infection clears

Related Topics

Frequently Asked Questions

References

1. Mayo Clinic. Mastitis — Symptoms and causes.
2. Centers for Disease Control and Prevention (CDC). Breastfeeding — Mastitis.
3. Academy of Breastfeeding Medicine. Mastitis Spectrum.
4. MedlinePlus, U.S. National Library of Medicine. Mastitis.