A new study found that perhaps the penicillin allergy might not be so straightforward. A group in Switzerland looked at 88 children who developed a rash after being on an antibiotic. A few months later they tested them for allergies to these antibiotics. Only 12% had positive skin tests, and only 7% developed a rash when taking the antibiotic again. However 2/3 tested positive for a virus, which likely caused the cough, runny nose...AND the rash. The antibiotic was likely a red herring.
So what does this mean for you? If your child has been labeled penicillin allergic based only on a rash (no breathing problems, hives, swelling or other symptoms) it may be worth doing a medically supervised oral challenge test to see if the rash really equalled an allergy.