There are too many causes of coughing up blood
to list them all. It would be important to be sure that the blood
is not originating in the nose, upper throat, sinuses or esophagus and then draining into the lungs.
Any lesion or spot in the lung, capable of repeatedly causing you to cough up blood, would usually be evident on a High Resolution CT Scan of the lungs. If that has not been done, it should be.