Mastitis- Causes, Symptoms, Diagnosis, Treatment and Ongoing care



  • Inflammation of the breast parenchyma, and possibly associated tissues (areola, nipple, subcutaneous fat) usually associated with bacterial infection (and milk stasis in the postpartum mother)
  • Usually an acute condition, but can become chronic cystic mastitis


  • Predominantly affects females
  • Mostly in the puerperium
  • Neonatal form
  • Post-traumatic:
    • Ornamental nipple piercing increases risk of transmission of bacteria to deeper breast structures:
      • Staph. aureus predominant organism
      • Epidemic form rare in the age of reduced hospital stays for moms and newborns


  • 2.5% of breast-feeding mothers develop nonepidemic mastitis.
  • Greatest incidence among breastfeeding moms 2–3 weeks postpartum
  • Neonatal form:
    • 1–5 weeks of age with equal gender risk and unilateral presentation
  • Pediatric form:
    • Around or after puberty
    • 82% of cases in girls

Risk Factors

  • Milk stasis:
    • Inadequate emptying of breast
      • Scarring of breast due to prior mastitis
      • Scarring due to previous breast surgery
    • Breast engorgement:
      • Interruption of breast-feeding
  • Ornamental nipple piercing increases risk of transmission of bacteria to deeper breast structures:
    • Staph. aureus predominant organism
  • Neonatal colonization with epidemic Staph.
  • Breastfeeding
  • Neonatal:
    • Bottle-fed babies
    • Manual expression of “Witch’s Milk”
    • Can predispose to lethal necrotizing fasciitis
  • Maternal diabetes
  • Maternal HIV
  • Maternal vitamin A deficiency

General Prevention

Regular emptying of both breasts and nipple care to prevent fissures when breast-feeding


  • Micro abscesses along milk ducts and surrounding tissues
  • Inflammatory cell infiltration of breast parenchyma and surrounding tissues
  • Nonpuerperal (infectious):
    • Staph. aureusBacteroides sp., Peptostreptococcus, Staph. (coagulase neg.), Enterococcus faecalis
    • Histoplasma capsulatum
  • Puerperal (infectious):
    • Staph. aureus, Streptococcus pyogenes (Group A or B), Corynebacterium sp., Bacteroides sp., Staph. (coagulase neg.), E. coliSalmonella sp.
    • MRSA (1)[C]
  • Rare secondary site for tuberculosis in endemic areas (1% of mastitis cases in these areas):
    • Single breast nodule with mastalgia
  • Corynebacterium sp. associated with greater risk for development of chronic cystic mastitis
  • Granulomatous mastitis:
    • Idiopathic


  • Puerperal:
    • Retrograde migration of surface bacteria up milk ducts
    • Bacterial migration from nipple fissures up breast lymphatics
    • Secondary monilial infection in the face of recurrent mastitis and/or diabetes (2)
    • Seeding from mother to neonate in cyclical fashion
  • Nonpuerperal:
    • Ductal ectasia
    • Breast carcinoma
    • Inflammatory cysts
    • Chronic recurring subcutaneous or subareolar infections
    • Parasitic infections: Echinococcus; Filariasis; Guinea worm in endemic areas
    • Herpes simplex (3)[C]
    • Cat scratch disease
  • Lupus

Commonly Associated Conditions

Breast abscess

breast parenchyma, breast feeding mothers, maternal diabetes, inflammatory cell, colonization,


  • Fever and malaise
  • Nausea ± vomiting
  • Localized breast tenderness, heat, and redness
  • Possible breast mass


  • Breast tenderness
  • “Hot cords burning in chest wall”

Physical Exam

  • Localized breast induration, redness, and warmth
  • Peau d’orange appearance to overlying skin

Diagnostic Tests & Interpretation

Mom can check if she produces salty milk from affected side (higher Na and Cl concentrations) as compared with unaffected side.


Rarely needed except for patients ill enough to be hospitalized:

  • CBC
  • Blood culture
  • In epidemic puerperal mastitis
    • Milk leukocyte count
    • Milk culture
    • Neonatal nasal culture


  • No imaging required for postpartum mastitis in a breast-feeding mother that responds to antibiotic therapy
  • Mammography for women with nonpuerperal mastitis
  • Breast ultrasound to rule out abscess formation in women:
    • Special consideration for this in women with breast implants who have mastitis

Diagnostic Procedures/Surgery

Options if further progression to abscess formation:

  • Needle aspiration
  • I and D
  • Excisional biopsy

Differential Diagnosis

  • Abscess
  • Tumor
  • Ductal cyst
  • Consider monilial infection in lactating mom, especially if mastitis is recurrent.


A recent Cochrane Review found that there is insufficient evidence to confirm or refute the effectiveness of antibiotic therapy for the treatment of lactational mastitis (4)[A].


  • Prioritized on the basis of likelihood of MRSA as etiologic factor and clinical severity of condition
  • Treat for 10–14 days (5)[B]
  • Prednisone for granulomatous mastitis (6)[C]

First Line

  • Outpatient:
    • Dicloxacillin 500 mg q.i.d.
    • Cephalexin 500 mg q.i.d.
    • TMP/SMX; DS b.i.d. (MRSA possible)
  • Inpatient:
    • Nafcillin 2 G q4hr
    • Oxacillin 2 G q4hr
    • Vancomycin 1 G q12hr (MRSA possible)
  • Breast-feeding beyond 1 month:
    • PCN, ampicillin, or erythromycin

Pediatric Considerations

  • TMP/SMZ given to breast-feeding mothers with mastitis can potentiate jaundice for neonates.
  • Clindamycin IM, IV, or p.o. with dosing based on age and weight

Second Line

  • If mastitis is odoriferous and localized under areola, add Metronidazole 500 mg t.i.d. IV or p.o.
  • Topical, oral, and neonatal nystatin if yeast is suspected in recurrent mastitis

Additional Treatment

Support's development and hosting

Issues for Referral

  • Abscess formation
  • Need for breast biopsy

Additional Therapies

  • Warm packs (or ice packs) to affected breast for comfort
  • The use of a breast pump may aid in breast emptying, especially if the infant is unable to assist in doing this.
  • Wear supporting bra that is not too tight

In-Patient Considerations

If a new mother is admitted to the hospital for treatment of her mastitis, rooming-in of the infant with the mother is mandatory so that breast-feeding can continue. In some hospitals, rooming-in may require hospital admission of the infant (7).

Initial Stabilization

  • Oral antibiotics
  • Frequent emptying of breasts if breast-feeding
  • Analgesics for pain:
    • Acetaminophen
  • NSAIDs

Admission Criteria

  • Failure of outpatient/oral therapy
    • Patient unable to tolerate oral therapy
    • Patient noncompliant with oral therapy
    • Severe illness without adequate supportive care at home
  • Neonatal mastitis


  • Breast-feeding/pumping of breasts encouraged
  • Start infant with feedings on affected side
  • Abscess drainage is not a contraindication for breast-feeding.

Discharge Criteria

  • Afebrile
  • Tolerating oral antibiotics well

Ongoing Care

Follow-Up Recommendations

Bed rest for lactating moms, up to bathroom


  • Encourage oral fluids
  • Multivitamin including vitamin A

Patient Education

  • Encourage oral fluids
  • Rest essential
  • Regular emptying of both breasts with breast-feeding
  • Nipple care to prevent fissures


  • Puerperal:
    • Good with prompt (within 24 hours of symptom onset) antibiotic treatment and breast emptying; 96% success rate
    • 11% risk of abscess if left untreated with antibiotics
    • Antibodies develop in breast glands within 1st few days of infection, which may provide protection against infection or reinfection.
  • Rare risk of abscess formation beyond 6 weeks postpartum if no recurrent mastitis


  • Breast abscess
  • Recurrent mastitis with resumption of breast-feeding or with breast-feeding after next pregnancy
  • Bacteremia
  • Sepsis


1. Gastelum DT, Dassey D, Mascola L, et al. Transmission of community-associated methicillin-resistant Staphylococcus aureus from breast milk in the neonatal intensive care unit. Pediatr Infect Dis J.2005;24:1122–4.

2. Lawrence R. Breastfeeding: a guide for the medical profession; Mosby-Yearbook; 2005;265.

3. Soo MS, Ghate S. Herpes simplex virus mastitis: clinical and imaging findings. AJR Am J Roentgenol. 2000;174:1087–8.

4. Jahanfar S, Ng CJ, Teng CL et al. Antibiotics for mastitis in breastfeeding women. Cochrane Database Syst Rev. 2009;CD005458.

5. Gilbert DN, Moellering RC, et al. The Sanford Guide to Antimicrobial Therapy 2010. Fourtieth Edition.

6. Kuba S, et al. Vacuum assisted biopsy and steroid treatment for granulomatous lobular mastitis. Surg Today. 2009;39:695–699.

7. Academy of Breastfeeding Medicine Protocol Committee. ABM clinical protocol #4: mastitis. Revision, May 2008. Breastfeed Med. 2008;3:177–80.

Additional Reading

Spencer JP et al. Management of mastitis in breastfeeding women. Am Fam Physician. 2008;78:727–31.

See Also (Topic, Algorithm, Electronic Media Element)

Algorithms: Breast Discharge; Breast Pain



  • Puerperal:
    • 675.24 Postpartum nonpurulent mastitis
    • 675.94 Unspecified postpartum infection of the breast and nipple
  • Non-Puerperal:
    • 611.0 Inflammatory disease of breast
    • 610.1Diffuse cystic mastopathy
  • 771.5Neonatal infective mastitis


  • 45198002 Mastitis (disorder)
  • 78697003 Nonpurulent mastitis associated with childbirth (disorder)
  • 83620003 Nonpuerperal mastitis (disorder)
  • 21648003 Chronic mastitis (disorder)
  • 3468005 neonatal infective mastitis (disorder)

Clinical Pearls

  • The 1st-line treatment for puerperal mastitis is Dicloxacillin 500 mg po. q.i.d. × 10–14 days. Most mastitis can be treated with oral therapy.
  • Complete emptying of the breasts on a regular schedule, avoiding constrictive clothing or bras that might obstruct breast ducts, meticulous attention to nipple care, and “adequate rest” and a liberal intake of oral fluids for the mother can all reduce the risk of a breast-feeding mother’s developing mastitis.
  • Among breast-feeding mothers, if the symptoms of mastitis fail to resolve within several days of appropriate management including antibiotics, further investigations may be required to confirm resistant bacteria, abscess formation, an underlying mass, or inflammatory or ductal carcinoma.
  • More than 2 recurrences of mastitis in the same location warrant evaluation with ultrasound and/or mammography to rule out an underlying mass.

About the author

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