INTRODUCTION

A breast abscess is a localized collection of pus in the breast tissue.

ETIOLOGY

Breast abscesses develop as a complication of mastitis (figure 1) [1]. In a review of 89 patients with breast abscesses requiring surgical intervention, 14 percent were lactational and 86 percent were nonlactational [2]. Breast abscesses were more common in African Americans, obese patients and smokers than in the general population.

Lactational abscess — Risk factors for lactational breast abscess formation include maternal age over 30 years of age, first pregnancies, gestational age ≥41 weeks gestation, and mastitis [3,4]. It is relatively uncommon for lactating women to develop a breast abscess as a complication of mastitis [3,5]. (See "Lactational mastitis".)

Nonlactational abscesses — Nonlactational abscesses can be classified as central, peripheral or skin associated. Patients with nonlactational abscesses, diabetics and smokers are likely to develop recurrent infections [6].

• Central (periareolar) nonlactational abscesses are usually due to periductal mastitis. (See "Mastitis and other skin disorders of the breast".)
• Peripheral nonlactational breast abscesses are less common than central abscesses and are sometimes associated with underlying disease states, such as diabetes, rheumatoid arthritis, steroid treatment and trauma.
• Skin associated infections are discussed separately (see "Mastitis and other skin disorders of the breast").