Problem: Amanda is a 7-year-old who is treated with amoxicillin for otitis media. After the first dose, Amanda's mother notices swelling of Amanda's lips and mild difficulty in breathing. Amanda is evaluated in the emergency room and a diagnosis of penicillin allergy is made. 2. The mother does not recall her daughter ever taking penicillin. Is this possible to develop an allergic reaction in the absence of previous exposure?