Here is what I learned. Abcesses are rare, occurring in 3-11 percent of women who have infectious mastitis. Abscesses can also develop with a recurrent plug that keeps occurring in the same spot. Abscesses can be diagnosed either by aspiration (lanced and drained with a needle by your doctor) or by ultrasound. If you are having an ultrasound, be sure to empty your breasts as much as possible before the test so that the technicians can more easily read the results. If you have an abscess aspirated, ask your doctor to culture the fluid that is drawn out so that an appropriate antibiotic can be prescribed.