Summary
Definition
History and exam
Key diagnostic factors
- fever
- decreased milk outflow
- breast warmth
- breast tenderness
- breast firmness
- breast swelling
- breast erythema
- flu-like symptoms, malaise, and myalgia
- breast pain
- breast mass
- fistula
Other diagnostic factors
- nipple discharge
- nipple inversion/retraction
- lymphadenopathy
- extra-mammary skin lesions
Risk factors
- female sex
- women aged >30 years
- poor breastfeeding technique
- lactation
- milk stasis
- nipple injury
- previous mastitis
- prolonged mastitis (breast abscess)
- prior breast abscess (breast abscess)
- shaving or plucking areola hair
- anatomical breast defect, mammoplasty, or scar
- other underlying breast condition
- nipple piercing
- foreign body
- skin infection
- Staphylococcus aureus carrier
- immunosuppression
- hospital admission
- breast trauma
- primiparity
- overabundant milk supply
- post-maturity (breast abscess)
- complications of delivery
- maternal fatigue
- tight clothing
- antifungal nipple cream
- fibrocystic breast disease
- cigarette smoking
- vaginal manipulation (breast abscess)
- poor nutrition
- antiretroviral therapy
Diagnostic investigations
1st investigations to order
- breast ultrasound
- diagnostic needle aspiration drainage
- cytology of nipple discharge or sample from fine-needle aspiration
- milk, aspirate, discharge, or biopsy tissue for culture and sensitivity
- histopathological examination of biopsy tissue
Investigations to consider
- pregnancy test
- blood culture and sensitivity
- mammogram
- milk for leukocyte counts and bacteria quantification
- culture from swab/aspirate from infant's and mother's oral cavity and nasopharynx
- FBC
- tuberculin skin test (purified protein derivative)
Treatment algorithm
Contributors
Authors

Assistant Professor of Surgery
University of Massachusetts Medical School - Baystate
Springfield
MA
Disclosures
HSM is a board member of the American Society of Breast Surgeons Foundation.
Dr Holly S. Mason would like to gratefully acknowledge Dr Jose A. Martagon-Villamil, Dr Daniel Skiest, Dr Gina Berthold, and Dr Liron Pantanowitz, previous contributors to this topic.
Disclosures
JAMV, DS, and GB declare that they have no competing interests. LP is a co-author of references cited in this topic.
Peer reviewers
Program Officer
National Institutes of Health
National Cancer Institute
Rockville
MD
Disclosures
ES declares that he has no competing interests.
Consultant Medical Oncologist/Senior Lecturer
Department of Medical Oncology
Imperial College/Imperial Healthcare NHS Trust
Charing Cross Hospital
London
UK
Disclosures
JS declares that he has no competing interests.
The G. Rainey Williams Professor of Surgical Oncology
University of Oklahoma
Oklahoma City
OK
Disclosures
WD declares that he has no competing interests.
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