17 yr old w/ Blood in BM but no hemorrhoids noted on exam

Hi all,

Our 17 yr old son just informed us that he has experienced blood in the toilet when he has a bm for the past two weeks. After having him leave one for us to examine, we found the bm itself covered in blood, blood in the water, and the toilet paper looked like someone had a nose bleed. We had him seen by his doctor who did an digital rectal exam. She said no fissures or hemorrhoids were apparent. We are now doing the fecal tests to see about parasites, amount of blood, etc. (we have to fill three different tubes each time he goes).

Since there weren't any hemorrhoids appreciated on the digital exam, is it still possible that that is what he has? If not, other considerations?

He says he has no pain, itching or other symptoms. He isn't constipated, but only goes every other day, but without difficulty. No fevers, diarrhea, abdominal pain or nausea. No weight loss (in fact he is about ten to fifteen pounds overweight for his age). His is a very sedentary life (not a sports fanatic), and he loves carbs (breads, pastas, etc.) He is on multiple meds for aspergers and a major depressive disorder, but his meds have not been changed in about a year.

Any insights would be appreciated.

Thanks

p.s. - I also noticed small white "spots" throughout the bm when taking samples, but didn't know if this was undigested food or sign of something else. Didn't look like anything specific like corn would, just tiny pin head sized spots.