My 2yr old daughter spewed up a little bit of blood?

My 19 month old has a cold at the moment she is constantly sneezing and coughing but tonight she spewed up her dinner and it had a little bit of blood in it. I think she may be getting her two yr old molars as her cheeks have been bright red, she's been scratching her ears, and has been very upset and grizzly for about 3 weeks. Could the blood be because of teeth or a cold I've never heard of this?