About 15% of the population have a suspected Penicillin allergy usually diagnosed in childhood with a rash and this affects antibiotic prescribing all their life. Recent research has shown that only 3% of those with a suspected Penicillin allergy in fact are allergic on challenge testing. The major problem is that skin prick tests, intradermal tests and RAST blood test have a very low diagnostic reliability, so to comfortably exclude a Penicillin allergy, one needs to do a challenge test in hospital which can be time-consuming and costly. Lecture at British Society Allergy Clinical Immunology meeting, Telford Sept 2014
