A 23-year-old woman who is currently breastfeeding and 6 weeks postpartum presents with a hard, red, tender, indurated area medial to her right nipple (Figure 94-1). She also has a low-grade fever. There is a local area of fluctuance, and so incision and drainage is recommended. The area is anesthetized with 1% lidocaine and epinephrine and drained with a #11 scalpel. A lot of purulence is expressed, and the wound is packed. The patient is started on cephalexin 500 mg qid for 10 days to treat the surrounding cellulitis and seen in follow-up the next day. The patient was already feeling better the next day and went on to full resolution in the following weeks.
Localized cellulitis and breast abscess in a breastfeeding mother. Note the peau d'orange appearance of the edematous breast tissue. (Reproduced with permission from Nicolette Deveneau, MD.)
The prevalence of mastitis is estimated to be at least 2% to 10% of breastfeeding women.1 Risk factors include partial blockage of the milk duct, pressure on the breast, oversupply of milk, infrequent feedings, rapid weaning, illness in mother or baby, maternal stress or excessive fatigue, maternal malnutrition, history of mastitis with a previous child, cracks and nipple sores, use of an antifungal nipple cream in the same month, and use of a manual breast pump.2
Breast abscess is an uncommon problem in breastfeeding women, with an incidence of approximately 0.1%.3 Risk factors include maternal age more than 30 years, primiparity, gestational age of 41 weeks, and mastitis.3,4 Breast abscess develops in 5% to 11% of women with mastitis, often caused by inadequate therapy.4
ETIOLOGY AND PATHOPHYSIOLOGY
Mastitis, defined as an infection of the breast, and breast abscesses are typically found in breastfeeding women (see Figure 94-1). A breast abscess can occur in older women unrelated to pregnancy and breastfeeding (Figure 94-2).
Mastitis is most commonly caused by Staphylococcus aureus, Streptococcus species, and Escherichia coli.
Recurrent mastitis can result from poor selection or incomplete use of antibiotic therapy, or failure to resolve underlying lactation management problems. Mastitis that repeatedly recurs in the same location, or does not respond to appropriate therapy, may indicate the presence of breast cancer.4
Breast abscess and cellulitis in a 40-year-old woman. Pus was already draining at the time of presentation, but a further incision and drainage through the openings yielded another 30 mL of pus. The patient was treated with oral antibiotics and scheduled to get a mammogram when the infection is cleared. (Reproduced with permission from Richard P. Usatine, MD.)