Lactating Breast Infection
Nursing mothers can develop cellulitis or abscess formation secondary to infection with staphylococcus aureus. The portal of entry is usually an irritated or cracked nipple. It is not known whether poor milk drainage secondary to blockage of a major duct is an initiating event.

Symptoms
Presenting features include pain, swelling and tenderness associated with redness of the overlying skin. There may be associated fever and chills.

Signs
Classically, a segment of the breast is inflamed, with erythema and tenderness present. In some instances, the entire breast is involved. There may be an associated cracked nipple. General signs of infection such as pyrexia and leucocytosis may be present. In the later stages, there may be a fluctuant mass indicating underlying pus.

Radiology
Mammography
This is only indicated if there is clinical uncertainty whether the appropriate diagnosis is an abscess or an inflammatory carcinoma. Often patients will be too uncomfortable to endure the breast compression required to perform a mammogram.

Ultrasound
Ultrasound is very useful in distinguishing between breast inflammation and abscess formation. It also guides needle aspiration, which may need to be repeated on several occasions before infection subsides.

Pathology
Macroscopic Appearance
There are no specific gross features.

Microscopic Appearance
The microscopic features are those of an acute inflammatory process.

Management
In the early phase of lactational mastitis, antibiotics can prevent abscess ormation. Emptying the breast as part of treatment can improve the outcome and shorten the duration of symptoms. Topical warmth may provide symptomatic relief. Patients with demonstrable pus either on clinical or ultrasound examination should have needle aspiration in addition to antibiotic therapy. It is our policy to treat these patients with repeated aspiration of pus, prescribe antibiotics and monitor resolution of the abscess by sequential ultrasound examination.

If the overlying skin is thinned or necrotic, we subject the patient to incision and drainage, which can be performed as an outpatient procedure under local anesthesia. It is rarely necessary to suppress lactation.

A.D. Purushotham, P. Britton and L. Bobrow
A prospective study of benign breast disease and the risk of breast cancer. JAMA 2002

References