Breast Infection (Mastitis)

Types of mastitis

For practical advice on managing mastitis while breastfeeding, see mastitis while breastfeeding.

Symptoms

• a painful, warm, swollen area in one breast, often wedge-shaped
• redness on lighter skin; on darker skin, the area may look darker, purple or not obviously red
• a firm or lumpy area
• burning pain during feeding
• fever of 38.3 °C (101 °F) or higher, chills, body aches and fatigue, similar to flu
• sometimes nipple cracks, pus or blood in the milk

Symptoms often start suddenly, over a few hours.

Causes and risk factors

Current thinking describes a mastitis spectrum: excess milk and swelling of the ducts and tissue cause inflammation; if it continues, bacteria can multiply, leading to bacterial mastitis and, potentially, an abscess.

Risk factors during breastfeeding:

• oversupply, often worsened by extra pumping
• poor latch or nipple damage that lets bacteria in
• missed or infrequent feeds and sudden changes in feeding pattern
• pressure on the breast from tight bras, bag straps or sleeping position
• previous mastitis
• illness, stress and exhaustion

Outside breastfeeding, smoking is the strongest risk factor for periductal mastitis. Nipple piercings, diabetes and a weakened immune system also raise risk.

Diagnosis

Mastitis is usually diagnosed from symptoms and a breast examination. Tests are used when:

• milk culture: symptoms do not improve after 48 hours of antibiotics, mastitis recurs, or it is hospital-acquired, to check for MRSA or resistant bacteria
• breast ultrasound: a lump persists or an abscess is suspected
• biopsy or mammogram: a non-breastfeeding woman, or symptoms not improving with treatment, because inflammatory breast cancer can look like mastitis

Treatment

Home care

• Continue breastfeeding or pumping as usual on demand. Do not stop suddenly; milk from the affected breast is safe for a healthy full-term baby.
• Avoid over-pumping or "emptying" the breast fully, which increases supply and inflammation.
• Apply ice or cold packs for 10 to 15 minutes between feeds to reduce swelling.
• Take ibuprofen for pain and inflammation, and acetaminophen (paracetamol) if needed. Follow the label dose. Both are compatible with breastfeeding.
• Use only gentle, light touch (lymphatic drainage) toward the armpit. Avoid deep massage, which can damage tissue.
• Rest, drink fluids and wear a supportive, non-tight bra.

Antibiotics

Antibiotics are needed when symptoms are not improving within 12 to 24 hours of home care, when the person is very unwell, or when there is nipple damage with infection. Common choices are dicloxacillin or cephalexin; clindamycin or others for penicillin allergy or MRSA. Courses usually last 10 to 14 days. Most people feel better within 2 to 3 days.

Breast abscess

An abscess is a pocket of pus. It feels like a firm, very tender, sometimes fluctuant lump, and fever may persist despite antibiotics. It is diagnosed by ultrasound and treated with needle aspiration, sometimes repeated, or a small surgical drain, along with antibiotics. Breastfeeding can usually continue.

Complications

• breast abscess (in a small percentage of lactational mastitis)
• recurrence
• reduced milk supply or early weaning
• sepsis, rarely

Prevention

• Feed on demand and avoid long gaps, while not overstimulating supply with excessive pumping.
• Get help from a lactation consultant for latch problems, nipple pain or oversupply.
• Avoid tight bras and pressure on the breasts.
• Wean gradually rather than abruptly.
• Stop smoking to reduce periductal mastitis.

Frequently asked questions

What are the first signs of mastitis?

The first signs are usually a tender, warm, swollen area in one breast, sometimes red or darker, followed within hours by flu-like symptoms such as fever, chills, aches and tiredness. Feeding from that breast may hurt.

Can you get mastitis when not breastfeeding?

Yes. Non-lactational mastitis occurs mainly in women who smoke (periductal mastitis), people with nipple piercings, diabetes or weakened immunity, and rarely in men. Because inflammatory breast cancer can look similar, breast redness when not breastfeeding should always be checked.

Does mastitis go away on its own?

Mild inflammatory mastitis often improves within 24 to 48 hours with ice, ibuprofen, rest and normal feeding. If fever and pain are not improving within 24 hours, or you feel very unwell, you probably need antibiotics. See a doctor.

Should I keep breastfeeding with mastitis?

Yes, in most cases. Continuing to feed normally helps recovery, and the milk is safe for a healthy full-term baby. Avoid overfeeding or overpumping the affected side. If feeding is too painful, express gently to comfort.

How do I know if mastitis has turned into an abscess?

Suspect an abscess if a firm, very tender lump persists, feels soft or fluid-filled, or fever continues after 48 hours of antibiotics. An ultrasound confirms it, and the pus can usually be drained with a needle.