What might cause this?

I really wasn't sure where to post this in the "Topic" menu, but I woke up this morning and I went to brush my teeth. Before I brush my teeth I usually blow my nose and spit a few times and couch a bit to get some mucus out of my throat(otherwise I have a slight cough with it coming up my throat and back down over and over again). So as I was clearing that up, I saw I had blood in it. I didn't have blood when I was blowing my nose, but when I was spitting I was. I don't smoke and am 16 years old. I have blood in my sputum I guess the correct word would be. I had a little cough yesterday and the same kind of cough still. Think it's a nasal infection or something? I do have a history of ear infections and respiratory problems, but I've never had blood in my sputum before. Now the blood is gone and doesn't occur when I try to spit but forcing mucus out of throat at same time(not sure what that action's called really).

[National Jewish Health]

The presence of a small amount of blood in the mucus you spit-up is abnormal, but not necessarily an indication of serious disease, especially in an otherwise healthy 16 year old.  In most instances, such blood originates in the nose, may then drain into the throat and is then spit-up.  Or it may originate in the gums.

The most important question is whether the bleeding does or does not recur.  If it does not recur and you have no other symptoms, you can probably forget about it.  But, if it recurs, even just one time, you should arrange for a nose and throat examination, preferably by an ENT specialist and get a chest x-ray.

Good luck.