Mastitis: Symptoms, Causes, and Treatment

Mastitis is an inflammation of the breast tissue, often caused by an infection. It's most common in breastfeeding women (lactational mastitis) but can occur in others. Symptoms include breast pain, swelling, warmth, and redness, along with flu-like symptoms. While uncomfortable, mastitis is treatable and doesn't necessarily mean you need to stop breastfeeding.

In plain words

Mastitis is swelling and pain in the breast, often from an infection. It's most common in breastfeeding moms but can happen to anyone. Your breast may feel sore, look red, and feel warm. You might also get chills and feel like you have the flu. The good news is mastitis can be treated, usually without stopping breastfeeding. Most cases get better with medicine and self-care.

What is Mastitis: Symptoms, Causes, and Treatment?

Mastitis is an inflammation of the breast tissue, often caused by an infection. It's most common in breastfeeding women (lactational mastitis) but can occur in others. Symptoms include breast pain, swelling, warmth, and redness, along with flu-like symptoms. While uncomfortable, mastitis is treatable and doesn't necessarily mean you need to stop breastfeeding.

Symptoms

Early symptoms

  • Localized breast tenderness: The affected area feels tender and may be painful to touch. Discomfort is often localized to one breast. (1) (5)
  • Breast warmth and redness: The breast may feel warm and show redness, often in a wedge-shaped pattern. (1) (5)
  • Breast swelling: The affected breast may become swollen and feel lumpy or hard. (1) (5)
  • Flu-like symptoms: Many people experience fever (101°F or higher), chills, fatigue, and body aches alongside breast symptoms. (1) (5)

Serious or emergency symptoms

  • Persistent painful lump: A lump that doesn't improve after antibiotics could indicate an abscess. Seek urgent medical care. (5)
  • High fever lasting more than 48 hours: A fever that doesn't break or worsens may signify a spreading infection. Seek urgent medical care. (5)
  • Red streaks extending from the affected area: Red streaks can indicate lymphangitis, a spreading infection requiring immediate treatment. Seek urgent medical care. (5)
  • Pus draining from the nipple: Pus may indicate an abscess or severe infection requiring drainage and antibiotics. Seek urgent medical care. (5)

Causes

Primary causes

  • Milk stasis in breastfeeding women: Mastitis often occurs when milk isn't fully removed from the breast, leading to blocked ducts and inflammation. (1)
  • Bacterial infection: Bacteria, commonly Staphylococcus aureus, can enter through cracked nipples, causing infection. (1)
  • Damaged nipples: Cracked nipples, nipple piercings, or eczema can allow bacteria to enter breast tissue. (1)
  • Smoking-related duct changes: Smoking can cause changes in breast ducts, increasing the risk of mastitis. (1)

Risk factors

Previous mastitis episode

Having had mastitis before increases the risk of recurrence. (3)

Sore or cracked nipples

Damaged nipples provide a pathway for bacteria to enter the breast tissue. (3)

Skipped feedings or pumping sessions

Infrequent milk removal can lead to milk stasis, increasing mastitis risk. (3)

Tight clothing

Clothing that restricts milk flow can contribute to blocked ducts. (3)

Diagnosis

Doctors typically diagnose mastitis based on symptoms and physical examination. They'll check for redness, warmth, and tender areas while noting any lumps. In complicated cases (eg, abscess suspected), ultrasound may be used. Rarely, a milk sample is cultured if infections recur or don't respond to first-line antibiotics.

Physical examination

To check for redness, warmth, and tender areas in the breast. (4)

Ultrasound

To detect an abscess in complicated cases. (4)

Milk culture

To identify the bacteria causing recurrent or persistent infections. (4)

Treatment

Medication options

Antibiotics

Antibiotics clear the bacterial infection causing mastitis. They're typically prescribed for 10-14 days. (2)

Pain relievers

Pain relievers reduce discomfort and inflammation associated with mastitis. (2)

Lifestyle and self-care

  • Frequent breastfeeding or pumping: Continuing to breastfeed or pump helps clear blocked ducts and maintain milk flow. (2)
  • Warm compresses: Applying warmth before feeding or pumping helps relieve pain and promote milk flow. (2)
  • Proper latch and feeding positions: Ensuring a proper latch and varying feeding positions helps prevent milk stasis and nipple damage. (2)
  • Hydration and rest: Staying hydrated and resting as much as possible supports recovery. (2)

Always discuss dosing and treatment changes with your own prescriber.

Possible complications

  • Breast abscess: Without treatment, mastitis can lead to abscess formation, requiring drainage. (6)
  • Recurrent episodes: Recurrent mastitis may indicate underlying issues like resistant bacteria or duct abnormalities. (6)
  • Systemic infection (sepsis): Rarely, untreated mastitis can lead to sepsis, a life-threatening condition. (6)

When to see a doctor

Routine follow-up

  • Schedule a visit if symptoms don't improve within 12-24 hours of self-care or worsen despite antibiotics. (3) (6)
  • See a doctor if red streaks appear or you feel generally unwell. (3) (6)

Seek emergency care

  • Seek emergency care for high fever (>101°F), vomiting preventing antibiotic intake, or rapid spreading of redness. (3) (6)

Frequently asked questions

What are the first signs of mastitis?

Early signs include localized breast tenderness, warmth, redness (often wedge-shaped), and swelling. Systemic symptoms like fever (usually >101°F), chills, fatigue, and body aches develop in about 80% of cases. Symptoms typically appear suddenly and affect one breast. (1) (5)

Can mastitis go away on its own?

Mild cases may resolve with frequent breastfeeding, massage, and warm compresses. However, if symptoms persist beyond 12-24 hours or include fever, antibiotics are usually needed to prevent complications like abscess formation. Without treatment, symptoms often worsen. (1) (5)

Is it safe to breastfeed with mastitis?

Yes, continuing breastfeeding is recommended unless a clinician advises otherwise. The milk is not harmful to infants, and frequent feeding helps clear the infection. If breastfeeding is too painful, expressing milk maintains supply. Specialists emphasize that stopping abruptly increases complication risks. (2) (3)

How long does mastitis last?

With appropriate treatment (antibiotics and continued milk removal), symptoms typically improve within 2-3 days. Full recovery usually takes about a week. Recurrent episodes warrant medical review to check for underlying causes like resistant bacteria or anatomical issues. (2) (3)

Can you get mastitis without breastfeeding?

Yes (non-lactational mastitis), though it's less common. Causes include nipple damage (piercings), smoking (duct changes), or certain autoimmune conditions. Treatment may involve antibiotics or further evaluation to rule out rare inflammatory breast conditions mimicking infection. (1)

References

  1. NHS — Mastitis source 1
  2. NHS — Mastitis - Treatment source 2
  3. CDC — Breastfeeding - Mastitis source 3
  4. MedlinePlus — Mastitis source 4
  5. MedlinePlus — Mastitis - Symptoms source 5
  6. CDC — Complications of Mastitis source 6