As with all other changes in the breast, cancer must always be excluded as the cause when nipples become inverted.
It can be normal to have inverted nipples and one or both of them may be inverted. It is abnormal to have a change in the shape or form of the nipple.
Any inflammatory condition of the breast can cause nipple inversion. Non-cancerous causes are:
- Duct ectasia
- Infection
- Abscess