Breast infections are divided into lactational and non-lactational, or puerperal and nonpuerperal categories. They can be associated with the superficial skin or an underlying lesion. Breast abscesses are more common in lactating women but do occur in nonlactating women as well. It is important to rule out more serious pathology like breast cancer when a non-lactational patient presents with signs and symptoms of breast abscess. The vast majority of these infections occur in females, but they can occur in males as well. Diagnosis and treatment for breast abscesses are not difficult, but there is a high rate of recurrence.
Lactational breast abscesses are most often caused by Staphylococcus aureus and Streptococcal species, Methicillin-resistant S. aureus is becoming increasingly common. Typically, non-lactational breast abscesses are a result of a mixed flora with S. aureus, Streptococcus, and anaerobic bacteria.
Lactation is the most common association with breast infections, present in 10% to 33% of these women. Lactational mastitis is present in 2% to 3% of lactating women, and 5% to 11% of these patients may develop an abscess. This is most common in women of childbearing age, with a mean age of 32 years. Nonlactating breast abscesses have a wider age range, with a peak incidence in the fourth decade of life. There is a strong association with diabetes and smoking with non-lactational breast abscesses. Obese patients and African Americans have a greater incidence of breast abscess. Nipple piercings have also been associated with subareolar breast abscesses in the nonlactating population.
To understand the pathophysiology of breast abscesses, you must understand the anatomy of the breast. The breast contains breast lobules, each of which drains to a lactiferous duct, which in turn empties to the surface of the nipple. There are lactiferous sinuses which are reservoirs for milk during lactation. The lactiferous ducts undergo epidermalization where keratin production may cause the duct to become obstructed, and in turn, can result in abscess formation. Abscesses associated with lactation usually begin with an abrasion or tissue at the nipple, providing an entry point for bacteria. The infection often presents in the second postpartum week and is often precipitated in the presence of milk stasis. The most common organism known to cause a breast abscess is S. aureus, but in some cases, Streptococci, and Staphylococcus epidermidis may also be involved. Women are encouraged to continue breastfeeding or using a breast pump to continue draining milk from the affected ducts.
The patient will usually provide a history of breast pain, erythema, warmth, and possibly edema. Patients may provide lactation history. It is important to ask about any history of prior breast infections and the previous treatment. Patients may also complain of fever, nausea, vomiting, purulent drainage from the nipple or site of erythema. It is also important to ask about the patient's medical history, including diabetes.
On exam, the patient will have erythema, induration, warmth, and tenderness to palpation at the site in question. It may feel like there is a palpable mass or area of fluctuance. There may be purulent discharge at the nipple or site of fluctuance. The patient may also have reactive axillary adenopathy. The patient may have a fever or tachycardia on the exam, although these are less common.
The cornerstone of diagnosis of a breast abscess is the physical exam. A complete blood count may be obtained to evaluate for leukocytosis, but it is not necessary. If there is any frank drainage, cultures can be obtained to help guide antibiotic treatment. A breast ultrasound may be obtained if there is a question of cellulitis versus abscess, to evaluate for a drainable fluid collection. On ultrasound, abscesses may appear as ill-defined masses with internal septations.
Incision and drainage are the standard of care for breast abscesses. If the patient is seen in a primary care setting by a provider that is not comfortable in performing these procedures, the patient may be started on antibiotics and referred to a general surgeon for definitive treatment. Needle aspiration may be attempted for abscesses smaller than 3 cm or in lactational abscesses. Non-lactational abscesses have a higher rate of recurrence and often require multiple drainage procedures. Incision and drainage have lower recurrence rates, but they are more invasive than needle aspiration and may lead to scarring and possible poor cosmesis. If there is a recurrence of an abscess after needle aspiration, incision and drainage should be performed. If there is a large cavity follow incision and drainage, packing of the cavity may be done to promote further drainage and prevent the skin incision from healing before drainage is complete. Typically, these wounds heal fairly quickly. If the cause of the abscess is an obstructed or ectatic lactiferous duct, surgical excision may be necessary.
A course of antibiotics may be given before or following drainage of breast abscesses. There are many options for treatment, and consideration must be given to the possible pathogens involved based on the patient's history. It is also important to consider if the patient is breastfeeding and whether the antibiotics given are safe in breastfeeding patients. Cultures should be obtained to guide antibiotic therapy, especially in recurrent breast abscesses. Some of the antibiotics to be considered are nafcillin, unasyn, augmentin, doxycycline, bactrim, clindamycin, vancomycin.
Patients with large breast abscesses or signs of sepsis should be considered for admission to the hospital. Large breast abscesses may need incision and drainage in the operating room, packing of the wound for healing by secondary intention, and possibly intravenous antibiotics.
Pain control with NSAIDs and/or prescription narcotics should also be considered.
Once the breast abscess is drained, the pain will quickly subside. Some patients may need NSAIDs for pain. In addition, one can apply a warm compress to soothe the inflammation and use moisturizer to prevent cracking of the nipples.
The patient should be educated on nipple and hand hygiene and prevent engorgement of the breast.
Patients may have recurrent or chronic infections, which can lead to chronic pain and scarring. In nonlactating women presenting with signs or symptoms of non-resolving breast abscess, a high index of suspicion for inflammatory breast cancer should be present. Patients should also be screened for new-onset diabetes.
Neonatal mastitis occurs in term or near-term infants. It is twice as common in females, and approximately 50% of these cases progress to breast abscess formation.
Other causes of breast abscesses include infected sebaceous cysts and hidradenitis suppurative, have specific evaluation and treatment.
There is no longer any question that breastfeeding has many health benefits for both the mother and the infant. In fact, the WHO recommends exclusive breastfeeding for the first six months of life and if possible, continue breastfeeding to age 18 months. Unfortunately, many women stop breastfeeding in the postpartum period because of the development of breast abscesses. The treatment of a breast abscess is usually with antibiotics, image-based aspiration, or incision and drainage.
While a breast abscess may sound like a trivial localized infection, there are no standard guidelines on its management. With the specialization of breast surgeons, many patients are needlessly admitted to the hospital and undergo unnecessary surgical procedures. Further, because of the nonuniformity in management, recurrence rates of breast abscess are also high. Because of nonuniformity in managing these patients, the outcomes also vary.   To lower health care costs and reduce the morbidity of unnecessary surgery, it is recommended that a streamlined approach with several types of healthcare professionals involved. The use of an interprofessional team should include the following:
Outcomes and Evidence-based Medicine
Because of the heterogeneity in management methods of breast abscess, there is in fact not enough data to state if needle aspiration is a better option than incision and drainage for a breast abscess. It is not known if an antibiotic should always be administered to women undergoing incision and drainage or aspiration. The few case series available reveal that the outcome for most women is excellent with any of these methods, but it is not known which is superior. However, with all three methods, recurrence of breast abscess is common. Thus, it is highly recommended that a standardized interprofessional approach be developed to manage breast abscess, lower the rates of recurrence, and improve outcomes.
With the lack of evidence-based medicine, it is important to err on the side of aspiration and prevent the empirical prescribing of antibiotics. Surgery should only be a last resort option in complex cases.