Breast Infection (Mastitis)
A painful breast infection most commonly affecting breastfeeding women
Quick Facts
- Type: Bacterial Infection
- ICD-10: O91
- Most Affected: Breastfeeding women
- Onset: Usually 1st 6 weeks postpartum
Overview
Mastitis is an inflammation and infection of the breast tissue that results in breast pain, swelling, warmth, and redness. This condition most commonly affects women who are breastfeeding (lactational mastitis), though it can also occur in women who are not nursing. Mastitis typically develops when bacteria enter the breast tissue through a cracked or sore nipple, or when milk ducts become blocked.
The condition affects approximately 10-30% of breastfeeding women, most commonly occurring within the first six weeks after delivery. However, mastitis can develop at any time during breastfeeding. While painful and concerning, mastitis is highly treatable with antibiotics and supportive care. Early recognition and treatment are important to prevent complications such as breast abscess formation.
Non-lactational mastitis can occur in women who are not breastfeeding and is less common. This type may be associated with conditions such as diabetes, compromised immune function, or breast trauma. Understanding the symptoms and seeking prompt medical attention can help ensure effective treatment and prevent serious complications.
Symptoms
Mastitis symptoms typically develop rapidly and can progress quickly if left untreated. The condition often affects only one breast, though bilateral involvement can occur.
Common Symptoms
Additional Symptoms
- Nipple discharge that may be purulent
- Difficulty breastfeeding on the affected side
- General fatigue and feeling unwell
- Enlarged lymph nodes in the armpit
- Dehydration from fever and reduced fluid intake
- Body aches and muscle pain
Warning Signs
Seek immediate medical attention if you experience:
- High fever (above 102°F/38.9°C)
- Red streaks extending from the breast
- Pus or blood in breast milk
- Severe, worsening pain despite treatment
- Signs of breast abscess (fluctuant mass)
- Symptoms that don't improve within 24-48 hours of antibiotic treatment
Causes
Mastitis is primarily caused by bacterial infection, though it can also result from inflammatory processes without bacterial involvement.
Bacterial Causes
The most common bacteria responsible for mastitis include:
- Staphylococcus aureus: The most frequent cause, including MRSA strains
- Streptococcus agalactiae: Group B streptococcus
- Escherichia coli: Gram-negative bacteria
- Enterococcus species: Often seen in hospital settings
How Bacteria Enter the Breast
- Cracked or damaged nipples: Providing entry point for bacteria
- Blocked milk ducts: Creating stagnant milk that promotes bacterial growth
- Poor hygiene: Transfer of bacteria from hands or baby's mouth
- Compromised skin integrity: From previous trauma or infection
Contributing Factors
- Incomplete breast emptying during feeding
- Infrequent feeding or sudden changes in feeding schedule
- Pressure on breasts from tight clothing or sleeping position
- Maternal stress, fatigue, or illness
- Previous history of mastitis
- Use of antifungal nipple creams (may alter normal skin flora)
Non-Lactational Causes
In women who are not breastfeeding, mastitis may be caused by:
- Chronic underlying conditions (diabetes, autoimmune disorders)
- Breast trauma or surgery
- Nipple piercings
- Smoking (impairs immune function)
- Duct ectasia or other breast disorders
Risk Factors
Several factors increase the likelihood of developing mastitis:
Breastfeeding-Related Risk Factors
- First-time mothers: Inexperience with proper latching and feeding techniques
- First few weeks postpartum: Highest risk period
- Cracked or sore nipples: Providing bacterial entry points
- Engorgement: Overfull breasts that don't empty completely
- Irregular feeding schedule: Long intervals between feeds
- Abrupt weaning: Sudden cessation of breastfeeding
- Blocked milk ducts: Previous episodes increase risk
Maternal Risk Factors
- Previous mastitis: History increases recurrence risk
- Age: Older mothers may have increased risk
- Stress and fatigue: Compromised immune function
- Poor nutrition: Inadequate caloric intake
- Anemia: Iron deficiency
- Diabetes: Impaired immune response
- Chronic illness: Conditions affecting immunity
Environmental and Lifestyle Factors
- Tight-fitting bras: Restricting milk flow
- Sleeping prone: Pressure on breasts
- Poor hygiene: Increased bacterial exposure
- Smoking: Impairs healing and immune function
- Hospital delivery: Exposure to resistant bacteria
Infant Factors
- Poor latch or positioning
- Infant illness affecting feeding
- Teething (may cause nipple trauma)
- Long feeding intervals
Diagnosis
Mastitis is primarily diagnosed based on clinical symptoms and physical examination. Laboratory tests and imaging may be needed in certain cases.
Clinical Assessment
- Medical history: Breastfeeding patterns, onset of symptoms
- Physical examination: Breast inspection and palpation
- Temperature measurement: Documenting fever
- Assessment of feeding: Observing latch and milk transfer
Laboratory Tests
Blood tests may be ordered in severe cases or when diagnosis is uncertain:
- Complete blood count (CBC): Elevated white blood cells indicate infection
- Blood cultures: If systemic infection is suspected
- C-reactive protein (CRP): Marker of inflammation
Milk Culture
Breast milk culture may be performed when:
- Symptoms are severe or recurrent
- Initial antibiotic treatment fails
- Hospital-acquired infection is suspected
- MRSA is suspected
Imaging Studies
Imaging is typically reserved for complicated cases:
- Ultrasound: To rule out abscess formation
- CT or MRI: For complex or recurrent cases
- Mammography: Usually avoided during lactation due to dense tissue
Differential Diagnosis
Conditions to consider in the differential diagnosis:
- Inflammatory breast cancer
- Blocked milk duct (without infection)
- Breast engorgement
- Galactocele (milk-filled cyst)
- Breast abscess
- Eczema or dermatitis of the nipple
Treatment Options
Mastitis treatment focuses on eliminating the infection, relieving symptoms, and maintaining breastfeeding when possible. Early treatment prevents complications and reduces symptom duration.
Antibiotic Therapy
Antibiotics are the cornerstone of mastitis treatment:
- First-line antibiotics:
- Flucloxacillin: 500mg four times daily for 10-14 days
- Cloxacillin: 500mg four times daily for 10-14 days
- Cephalexin: 500mg four times daily for 10-14 days
- For penicillin allergy:
- Erythromycin: 500mg four times daily
- Clindamycin: 300mg four times daily
- Azithromycin: 500mg daily for 3 days
- For MRSA suspected cases:
- Clindamycin: 300-450mg three times daily
- Trimethoprim-sulfamethoxazole: Based on culture results
Continued Breastfeeding
Breastfeeding should continue during treatment:
- Safe for infant - antibiotics used are compatible with breastfeeding
- Helps drain the breast and prevent abscess formation
- Start feeding from unaffected breast first
- Empty affected breast completely
- Use breast pump if direct feeding is too painful
Pain Management
- Oral pain relievers:
- Ibuprofen: 400-600mg every 6 hours (anti-inflammatory)
- Acetaminophen: 500-1000mg every 6 hours
- Can be used together for better pain control
- Topical treatments:
- Warm compresses before feeding
- Cold compresses after feeding
- Lanolin cream for nipple care
Supportive Care
- Rest: Adequate sleep and reduced activity
- Hydration: Increased fluid intake
- Nutrition: Maintain adequate caloric intake
- Proper positioning: Correct latch and feeding position
- Frequent feeding: Every 2-3 hours to prevent engorgement
- Breast massage: Gentle massage toward nipple
Treatment for Complications
If abscess develops:
- Ultrasound-guided needle aspiration
- Surgical drainage if needed
- Extended antibiotic course
- Close follow-up monitoring
Prevention
While not all cases of mastitis can be prevented, several strategies can significantly reduce the risk:
Proper Breastfeeding Techniques
- Correct positioning and latch: Seek lactation consultant help early
- Frequent feeding: Every 2-3 hours to prevent engorgement
- Complete emptying: Ensure breast is well-drained after feeding
- Alternate starting breast: Begin feeds from different sides
- Gradual weaning: Avoid abrupt cessation of breastfeeding
Breast Care
- Gentle cleaning: Wash hands before handling breasts
- Nipple care: Allow nipples to air dry after feeding
- Proper-fitting bras: Avoid tight or underwire bras
- Treat nipple problems early: Address cracks or soreness promptly
- Avoid unnecessary products: Limit use of creams or ointments
Lifestyle Modifications
- Adequate rest: Get sufficient sleep when possible
- Stress management: Practice relaxation techniques
- Proper nutrition: Maintain balanced diet with adequate calories
- Stay hydrated: Drink plenty of fluids
- Avoid smoking: Impairs immune function and healing
Early Intervention
- Treat blocked ducts promptly
- Address feeding difficulties early
- Seek help for persistent breast pain
- Monitor for early signs of infection
- Maintain regular pediatric and obstetric follow-up
For High-Risk Women
- Extra lactation support and education
- More frequent monitoring in early postpartum period
- Prompt treatment of risk factors (diabetes, anemia)
- Consider prophylactic measures in recurrent cases
When to See a Doctor
Prompt medical attention is important for proper treatment and to prevent complications:
Seek Immediate Medical Care
- High fever (above 102°F/38.9°C)
- Severe breast pain that prevents normal activities
- Red streaks extending from the breast
- Signs of abscess (fluctuant, tender mass)
- Pus or blood in breast milk
- Symptoms of severe illness (vomiting, severe fatigue)
- Inability to care for baby due to symptoms
Schedule Same-Day Appointment
- Fever with breast pain and redness
- Flu-like symptoms with breast symptoms
- Breast pain that worsens despite home care
- Difficulty breastfeeding due to pain
- Symptoms that develop rapidly
Schedule Routine Appointment
- Persistent breast tenderness without fever
- Concerns about breastfeeding technique
- Recurrent blocked ducts
- Questions about breast care during lactation
- Follow-up after mastitis treatment
Follow-up Care
- Return if symptoms don't improve within 24-48 hours of treatment
- Complete full course of antibiotics as prescribed
- Monitor for signs of recurrence
- Seek lactation support if feeding difficulties persist
Frequently Asked Questions
Yes, you should continue breastfeeding during mastitis treatment. It's safe for your baby and actually helps your recovery by draining the breast. The antibiotics used to treat mastitis are safe during breastfeeding. If direct feeding is too painful, you can pump and bottle-feed the milk.
With proper antibiotic treatment, mastitis symptoms typically begin to improve within 24-48 hours. Most women feel significantly better within 2-3 days. The full course of antibiotics (usually 10-14 days) should be completed even if symptoms resolve earlier to prevent recurrence.
Mastitis itself is not contagious. The bacteria causing the infection are typically already present on the skin or in the environment. Your baby and family members cannot "catch" mastitis from you. However, good hygiene practices are always recommended.
Mastitis may temporarily reduce milk supply in the affected breast. Continuing to breastfeed or pump frequently helps maintain supply. Most women's milk production returns to normal after the infection resolves. Severe or recurrent mastitis may have longer-term effects on supply.
Yes, though less common, mastitis can occur in non-breastfeeding women. This may be associated with conditions like diabetes, immune system problems, breast trauma, or nipple piercings. The treatment approach is similar but may require additional evaluation for underlying causes.
Prevention strategies include proper breastfeeding technique, frequent feeding, complete breast emptying, good hygiene, adequate rest, and addressing any breastfeeding problems early. If you've had mastitis before, work closely with a lactation consultant to identify and address potential contributing factors.
References
- Academy of Breastfeeding Medicine. Clinical Protocol #36: The Mastitis Spectrum. Breastfeed Med. 2022.
- World Health Organization. Mastitis: Causes and Management. WHO. 2023.
- American College of Obstetricians and Gynecologists. Breastfeeding Challenges. ACOG. 2023.
- Jahanfar S, Ng CJ, Teng CL. Antibiotics for mastitis in breastfeeding women. Cochrane Database Syst Rev. 2022.
- International Lactation Consultant Association. Clinical Guidelines for Mastitis. ILCA. 2023.