Periareolar breast abscess has been an elusive condition, with much debate about its etiology over the last several decades. Presenting symptoms include nipple discharge, mastalgia, and recurrent abscesses with draining fistulas. Many experts disagree about whether this condition develops when inflammation of the duct leads to dilation or whether it begins with dilation that leads to inflammation. Because the frequency of asymptomatic dilated ducts found incidentally in patients during surgery or upon autopsy exceeds that of patients with symptomatic duct dilation or ectasia, we believe that mechanical obstruction with associated retention of secretions is at the core of this disease process. In this article, we term and characterize mammary-duct-associated inflammatory disease as a 3-phase pathologic process that leads to recurrent nonlactational periareolar breast abscess in nonpuerperal women. Effective treatment of abscesses should be based on the disease's pathogenic process and should include excision of all involved ducts. Treated by this method, patients appear to experience minimal sequelae and low recurrence of abscesses.