While mastitis is almost never an emergency, left untreated it can lead to a breast abscess, which is a collection of pus in a hollow area in the breast. Your doctor may need to drain the abscess. A wiser course is to never let mastitis lead to an abscess.

Can mastitis be serious?

Mastitis can occur with or without the presence of infection. As it progresses, mastitis can cause the formation of a breast abscess. This is a localized collection of pus within breast tissue. Severe cases of mastitis can be fatal if left untreated.

What happens if you dont treat mastitis?

If mastitis isn't treated properly, an abscess (collection of pus) may develop. This could form a mass in your breast. Abscesses are usually painful. They normally have to be drained surgically.