Breast Pain and Fever While Nursing: Could It Be Mastitis?

Breast pain with a fever while nursing can be mastitis, an inflammation of breast tissue that may or may not involve infection. It often shows up as a sore, red, warm area with flu-like achiness. Mastitis can usually be treated, but it needs a same-day call to your clinician, and certain signs call for emergency care. This article covers the usual symptoms, what may cause it, what you can do at home, how clinicians evaluate it, and when to get help.

What mastitis feels like when you are nursing

Mastitis is inflammation of breast tissue. When it happens during breastfeeding it is often called lactational mastitis. MedlinePlus lists mastitis among the breast conditions that can affect women, and it is one of the problems nursing parents most often ask about.

Common features include:

• A tender, hard, or swollen area in one breast, sometimes wedge-shaped
• Skin over the area that looks pink or red and feels warm
• Burning or sharp pain, which may be worse during feeding
• Fever, chills, body aches, and feeling run down, similar to the flu

Symptoms often affect one breast, though both can be involved. Not everyone has every feature. A fever is a reason to call your clinician, even if the breast looks only mildly changed.

Why breast pain and fever can happen together

Several factors may contribute, and the exact mechanism is not fully understood. Milk that is not drained well from part of the breast can build up. Research on human milk has found that milk from breasts with mastitis can show signs of inflammation, such as higher levels of immune signaling molecules and more white cells. Bacteria on the skin or in the baby's mouth may enter through a cracked or sore nipple, and in some cases infection develops. In other cases inflammation occurs without a clear infection.

Situations that may raise the chance of milk building up include:

• A baby who latches poorly or does not empty the breast well
• Missed or long gaps between feeds, such as when a baby starts sleeping longer
• Sudden weaning
• Pressure on the breast from a tight bra, a bag strap, or sleeping position
• Sore or cracked nipples
• Being very tired or run down, which is common in the early postpartum weeks

A plugged duct can feel like a firm, tender lump without fever. It may come before mastitis, but a plugged duct does not always progress.

What you can do at home while you arrange care

Home steps support treatment but do not replace a call to your clinician when you have a fever. Common comfort measures include:

• Keep feeding or expressing. Milk from a breast with mastitis is generally considered safe for the baby, though you can confirm this with your clinician or your baby's pediatrician. Continuing to drain the breast may help ease pressure.
• Check the latch. A lactation consultant can watch a feed and adjust positioning. Many hospitals and pediatric offices can refer you.
• Use gentle technique. Very hard massage or aggressive pumping may worsen swelling in some people. Light touch is usually recommended.
• Try cold or warm compresses. Some people find warmth before a feed or cool packs after a feed more comfortable. Evidence on the best approach is limited.
• Rest and fluids. Sleep and hydration can help while your body is fighting inflammation.
• Wear a comfortable bra. Avoid tight underwires or straps that press on the sore area.

For pain or fever relief, ask your clinician or pharmacist which over-the-counter medicine fits your situation and the dose on the label. Many nursing parents use acetaminophen (Tylenol) or ibuprofen, but your own health history matters.

How clinicians evaluate breast pain with fever

Clinicians combine your history, an exam of the breast and nipple, and sometimes testing. They will usually ask when symptoms began, whether you have a fever, how feeding is going, and whether you have had mastitis before. They may check your temperature and look for a firm or fluctuant area that could suggest an abscess.

If an abscess is suspected, an ultrasound may be used. Imaging reviews describe ultrasound as a common first test for suspected breast infection in lactating patients, and it can help show whether there is a pocket of fluid. A needle sample of fluid may be sent for culture in some cases.

Mastitis that does not improve, keeps coming back, or happens outside the nursing period needs a closer look. Skin conditions of the breast and nipple, such as eczema or yeast-related changes, can occur during lactation and may look similar, as reviewed in medical literature on breast and nipple dermatoses in lactation. Less common inflammatory conditions, such as granulomatous mastitis, exist but are much less common than everyday lactational mastitis, and one symptom alone does not establish them. Rarely, breast cancer can cause redness and swelling of the breast; this is much less common than mastitis, and clinicians consider it when symptoms do not respond to treatment.

Treatment: antibiotics and other care

Treatment depends on how you look and feel. Some mild cases improve with better milk removal and comfort measures. When a clinician suspects bacterial infection, or when symptoms are significant or are not improving, they may prescribe an antibiotic. Which one is chosen depends on your allergies and other factors.

If you are prescribed an antibiotic, take it as directed and ask your prescriber or pharmacist about its safety with breastfeeding. We cover that question in our article on whether antibiotics are safe while breastfeeding. Do not change the timing or dose on your own, and tell your clinician if you feel worse after starting treatment, since that may mean the plan needs to be adjusted.

An abscess is a collection of pus that may form when mastitis is not improving. It may need drainage by a clinician, sometimes with ultrasound guidance. A published report on lactational mastitis discusses ways of draining milk and pus to try to prevent an abscess, but management is individual, so follow the plan your clinician gives you.

Warning signs that need more than home care

Mastitis can occasionally progress to a more serious infection that spreads beyond the breast. Signs that may point to a body-wide infection (sepsis) include a fast heartbeat, fast breathing, confusion, shaking chills, severe weakness, or feeling very unwell. These need emergency care. A fever alone is not a 911 line, but a fever together with these features is.

A painful, firm, localized lump that does not soften, spreading redness, or pus or blood from the nipple needs prompt evaluation by a clinician, since an abscess may be present.

Mastitis and postpartum life

Mastitis often arrives during an exhausting stretch. If you are struggling with low mood, anxiety, or hopelessness on top of the pain, that deserves attention too. Our article on postpartum depression and the baby blues explains how to tell the difference. If you ever have thoughts of harming yourself, call or text the 988 Suicide and Crisis Lifeline, or call 911 if you are in immediate danger.

If you are worried your baby is not feeding well because of breast pain, our article on how to tell whether your baby is getting enough breast milk may help. MedlinePlus also has a general overview of breastfeeding and common problems.

Lowering the chance of it happening again

• Feed on demand and avoid long gaps when possible, and change gradually when weaning
• Ask a lactation consultant to check latch and positioning
• Treat sore nipples early and tell your clinician about cracks or persistent pain
• Avoid pressure from tight clothing or straps
• Tell your clinician if mastitis keeps returning in the same area, so they can look for a cause

Prevention is not perfect, and mastitis can happen even when everything seems to be going well. Having it does not mean you did something wrong.

When to Seek Medical Care