For about a week, my breasts were extremely tender, achy, warm and swollen. I also experienced a burning and stinging sensation. My doctor prescribed an antibiotic to clear the infection, which I think has been helping. She told me that women who breastfeed often get this infection. But, I am 42, and neither breastfeeding nor pregnant. What could have caused this infection? Is there a medical term? And, is there anything I can do in the future to prevent it from happening again?

K.S.

Mastitis is the medical term for a breast infection. It is most common in women who are breastfeeding, due to bacteria from the baby's mouth or through small cracks in the nipple. In nonlactating women, mastitis can develop as the result of trauma (injury) to the breast, including scratches or cuts, or from oral stimulation of the breasts by a sexual partner. The infection is caused by normal bacteria that reside on the skin (most often Staphylococcus aureus) getting past the normal protective barrier of the skin and infecting underlying breast ducts. Antibiotics will usually take care of the infection, but sometimes a doctor must cut into the area and drain it.

In nonlactating women, it is important to distinguish mastitis from inflammatory breast cancer. Inflammatory breast cancer can often look like an infection, but it will not resolve with a course of antibiotics. If symptoms of pain, redness persist or you feel a mass, you need a biopsy.

If indeed this is mastitis, be careful about hygiene. Keep your breasts clean with a mild soap. Avoid scratching the skin. Avoid oral stimulation of your nipples, especially if your nipples are cracked. And, again, if the symptoms do not go away fairly rapidly with a course of antibiotics, insist on a second opinion from a breast surgeon.