Mark E. Reiber, M.D., F.A.C.S., F.A.A.O.A.

 

What is Allergy? When asked this question, people describe sneezing, watery eyes, and nasal congestion, but they can’t define “allergy”. What causes allergy? Why do you have allergies? Why do you suffer greatly while someone else has mild symptoms? Why might allergies start in adulthood? What can you do to prevent allergies?

 

Studies show that most patients feel they understand their allergies, but when quizzed, less than half knew the immune system was involved.  Few could explain the differences between types of allergy medications or even which type they were taking.

So what do you need to know without having to get a medical degree?

 

 Let’s first define the term, “antigen”. It’s the smallest protein molecule causing allergic symptoms. When we say you are allergic to cats, it’s not the whole cat, just the Fel protein in a cat’s saliva that gets on its hair when it licks its fur. 

Protein antigens are found in pollens, molds and all allergic substances.  

 

 To be allergic, you must possess both a unique allergy gene for each antigen, and a repetitive exposure to that antigen.

 

You get 23 pairs of chromosomes, one from each parent. Each is a long strand of DNA molecules made up of millions of genes and a blueprint of information instructing the cell how to grow, work and behave. Within immune cells are unique genes for each antigen to which you have the potential be allergic. Rarely is anyone allergic to only one thing. 

 

 Genes are copied into RNA and then made into proteins.   Proteins are the workers performing the function and structure of the cell. Along the way of going from DNA to RNA to proteins are many steps for control and regulation for functions.

If one parent has allergies, you have a 33% chance of developing allergies, and 50% chance if both parents are affected. If genes alone accounted for allergies, these numbers should be 50% and 100%.   There are many factors that regulate gene expression and alter these numbers. Patients with the same “allergy gene” can have different expressions and show mild, moderate or severe symptoms.  

 

Just having the allergy gene isn’t enough, there must be repeat exposures. With first contact, your system detects, processes, and reacts without symptoms. Subsequent exposures cause increasingly greater responses until a full-blown reaction is seen after about the fifth exposure. Studies show some ages may be more susceptible to sensitization than others.   Exposing young children to cats or certain foods may be more likely to lead to allergy than exposures later in life.

 

How and why do allergic reactions happen?

 Our immune system is a complex array of chemical reactions designed to protect us from the outside world.   It recognizes foreign from self and eliminates or isolates invaders.

 

Common invaders include bacteria, viruses, chemical irritants and toxins, as well as allergens. The symptoms we experience are the consequences of an immune response. Fever, for example, results from a white blood cell product, interleukin, designed to raise the body’s temperature and improve immune system efficiency. The itchy, watery nose and sneezing you experience during an allergic attack is from the release of histamine by immune cells in the nose.

 

When working as intended, our immune system eliminates foreign substances without harm; however errors can occur. In allergy, commonly encountered substances are recognized as harmful and the response is overly aggressive.

 

 An even greater problem can occur when the immune system mistakenly recognizes its own body as foreign. In medical terms, this is an “autoimmune” disease. Rheumatoid arthritis and lupus are common examples.   

 

            Immune reactions are complex and intertwined like an elaborate interstate highway system, with multiple branching roads.   There can be many triggers initiating a reaction and different pathways taken. Viruses, bacteria, toxins, pollutants, and allergens are all triggers. Immune reactions for bacterial and viral infections take different paths, and for allergies, there are at least four unique types of reactions. 

Poison ivy is one type of allergic reaction known as delayed hypersensitivity. It takes several hours to develop and is rarely lethal. A peanut allergy reaction on the other hand, is immediate and life threatening. 

 

A powder keg, waiting to explode: 

Once the immune system has been primed by exposures, it is set to react more easily and severely, like an explosion erupting through a fireworks factory. Light one fuse and soon the whole place is exploding. When allergies are bothering you, it may seem like anything will start you sneezing or blowing. When we treat nasal allergy, we concentrate on prevention and early intervention.   We want to prevent the triggers and block the highway before the paths get too complicated.

 

            Allergies are a result of your genes and your exposures. The immune system is complex and functions as a defense system for the body. Allergy is an overly enthusiastic reaction to common proteins in the environment. There are many triggers, but once your immune system starts reacting it is more likely to do so again, and more severely. Prevention and early intervention is the best approach.

 

2-13-08