Mastitis is an inflammation of the breast. There are three principal causes:
- Infection, which accounts for about half of cases and is almost always
- Blocked ducts that force the milk to drain into nearby breast tissue, causing the
tissue to become inflamed.
Mastitis most commonly affects women who are breast-feeding but sometimes occurs
in women that are not in that condition.
Symptoms are flu-like.
The lump felt in one breast is usually caused by milk getting into the breast
tissue instead of the milk ducts.