red belly and spots

Question
I notice when he goes outside or gets real excited and aggressive his underbelly will turn a red light pink coat on his skin aned it his white ears the inside is a darker red too it comes and goes, Don't know if this is from him getting excited, aggressive  he is 19 weeks old. He is a White English Pet Bull mixed with boxer.

Answer
If you only notice the red areas when he gets excited or is aggressive and I am assuming that when he is outside he is also running and playing, I think the redness is just from increased blood flow.  Just like when people get flushed, it sounds like that is what is happening with your dog.

If you notice any itching or discomfort, you should see your vet.