Hypersensitivity to Penicillin based and non Penicillin based antibiotics are commonly reported.
They can be classified as immediate or non-immediate depending on the time interval of drug administration and reaction. Immediate is usually under an hour and it can be presented with hives, swelling, asthma symptoms or anaphylaxis, this is mediated by IgE antibodies. Non-immediate occur more than 1 hour after administration. This usually presents with a rash. The evaluation of drug allergy is complicated. The history is most important and testing is based on the time of the reactions. Immediate reactions can be tested by skin testing, IgE immunocap and/or drug challenges. Non immediate reactions can be tested by delayed patch tests and challenges as well. The skin tests have only been approved for Penicillin and its deratatives.