Allergies and our immune system

Have you seen The Big Bang Theory episode Penny decides to throw Leonard a surprise birthday party?  Howard's duty is to keep Leonard busy while Penny plans Leonard’s party?  Howard decides to fake an allergic reaction and goes to a hospital emergency room claiming he is suffering an allergic reaction to peanuts.  The nurse takes one look at him and tells him to get lost.  He shows no symptoms of an allergic reaction.  So in an effort to keep Leonard busy, Howard wanders off and eats peanuts.  Howard returns to the emergency room desk with his face grossly swollen and reddened and he was having difficulty breathing.  He approaches the nurses’ desk and gets a different response this time as the nurse calls for immediate treatment for him.  His swollen, reddened face and gasping breathing display symptoms of an allergic reaction.   

What is an allergic reaction?  It’s a hypersensitive, overreaction response by the immune system to what should be a harmless substance.  I’m not allergic to peanuts so I can enjoy peanuts any time I want (unless my body decides to react to react in an allergic manner). Poor Howard on Big Bang Theory had a serious allergic response to peanuts.  Some people are so sensitive to peanuts that the presence of peanut dust can cause an allergic response.  More next time about allergies.