How to tell if baby's allergic to amoxicillin?

Amoxicillin reaction: The usual findings of an antibiotic allergy including Amoxicillin are typically rash such as hives or swelling. More severe symptoms can include vomiting/diarrhea, wheezing or anaphylaxis. The symptoms can start at the end of the first course within hours or a couple of days after having tolerated Amoxicillin in the past or even several days after the course of antibiotics has ended.