Sneezes, wheezes, runny noses and red eyes - this episode is all about allergies. An allergic reaction is when your immune system reacts to something harmless – like peanuts or pollen – as if it was a parasitic invader. It’s a case of biological mistaken identity. Professor Judith Holloway from the University of Southampton guides our sleuths through the complex immune pathways that make allergies happen and tells the scary story of when she went into anaphylactic shock from a rogue chocolate bar. Professor Adam Fox, a paediatric allergist at Evelina Children’s Hospital, helps the Drs distinguish intolerances or sensitivities – substantial swelling from a bee sting, for example - from genuine allergies. Hannah’s orange juice ‘allergy’ is exposed as a probable fraud! Hannah and Adam explore why allergies are on the increase, and Professor Rick Maizels from the University of Glasgow shares his surprising research using parasitic worms to develop anti-allergy drugs! Producer: Ilan Goodman Contributors: Professor Judith Holloway, Professor Adam Fox, Professor Rick Maizels