Hi,
Bloody discharge from the nipple can be associated with many different conditions.Most often it could be an intraductal papilloma which is a non cancerous tumor.
Also,the bleeding can happen from inflammation in the ducts, reaction to drugs, dilatation of the mammary ducts(duct ectasia), and less commonly a cancerous tumor.The bloody discharge must be examined under the microscope(called cytological examination) for a diagnosis. So, please see your physician as soon as possible to have diagnostic tests done. Cytology is definitely recommended when the discharge from the nipple is bloody.
Best wishes...