6yr old has strep throat started amox yest. today had itchy red thigh he took amox many times before in oct took for 6 out of 10 days is this allergy ?

Can be allergy: Someone can develop an allergy to a medication at anytime, so i prefer you call the pediatrician and let them look at the rash, you don't want to risk it spreading more if he continues on it.

Maybe: It's too soon to tell. This is a tough question and you won't get the same answer from all providers. Some would say stop the medicine. Others would say you might unnecessarily deprive your child of pencillin drugs for the rest of his life if you declare him to be allergic. Only one thing is certain: the more widespread this rash becomes, the more likely he is to have become allergic to the drug.