Antibiotics can cause allergy

I have a kid who is 2 yrs and 11 months old. He had a ear infection couple of weeks back. I took him immediately to the doctor. Doctor prescribed an antibiotitcs and that little guy developed allergy to that antibiotic. He had rashes all over his body.

After one week of another antibiotics and benadryl, he is ok now. Back to normal.

Thanks for reading.