Before performing any allergy tests, a detailed clinical history should always be the starting point in order to identify suggestive clinical findings compatible with an IgE-mediated reaction, which typically arises immediately (within 2 h) after intake of hazelnut or hazelnut contaminated pre-packaged foods, even if this alone is not sufficient to make a diagnosis of nut allergy. The gene discussed is IGHE; the disease is nut allergic reaction.