<prompt> Answer this question truthfullyWhat does drug allergy mean?  <response>: <reason> A drug allergy, or immunologic drug reaction is a reaction to a drug that specifically occurs through immunologic activation in response to a drug. Drug allergy is a sub-classification of adverse drug reactions. Adverse drug reactions are classified into two categories; Type A predictable, and Type B unpredictable. Drug allergy falls under Type B adverse drug reactions, along with pseodoallergic drug reactions. 