Brief, focused history can be VERY helpful.
How long after beginning penicillin did the reaction occur?
Was there any wheezing, throat or mouth swelling, urticaria, or angioedema?
If a rash occurred, what was the nature of the rash? Where was it and what did it look like? Did the rash include any blistering or exfoliative features?
Was the patient on other medications at the time of the reaction?
Since then, has the patient ever received another penicillin or cephalosporin? Ask about trade names like Augmentin, Keflex, Ceftin, Vantin
If the patient received a beta-lactam subsequent to the initial reaction, what