The immunoglobulin E (IgE)-mediated hypersensitivity reactions are triggered by foods, preservatives such as sodium benzoate used in peanut butter, dust, drugs like angiotensin-converting enzyme inhibitors (ACE) like captopril, enalapril, lisinopril and pollens, and contact allergies started by prolonged contact with dental rubber dams and cosmetics. The gene discussed is IGHE; the disease is Allergy.