[Duke The Boxer]

hey Patty, Duke is not 7 months and 51 pounds! So excited. I started to notiece some weird patches and i took him to the vent and it turned up to be demodetic mange or demodex. After he went on the medicine for the mange thats when he gained the 8 pounds in 3 1/2 weeks. But recently sometimes in the mornings he will throw up some or all of his food. It is not everyday or even every other day so thats why its confusing me.
Any thoughts? He is transitioning into wellness core puppy which he had been on before and never had these problems. Could it be food related?