What is an Allergy and why are some people Allergic ?

Posted by Christine Handler-Kralits on

An allergy is a specific reaction by the body's immune system to a normally harmless substance. Some types of allergens that cause reactions include:

  • Pollen
  • House and Dust Mites
  • Mold Spores
  • Food
  • Latex Rubber
  • Insect Venom
  • Medicines


Why are some people allergic?

Scientists think that some people inherit a tendency, sensitivity to be allergic from one or both parents, however, people don't inherit a tendency to be allergic to any specific allergen.

What is an allergic reaction?

The immune system functions as the body's defence system against invading germs like bacteria and viruses. It's when the body's immune system over reacts to an allergen as if it were a germ, that an allergic reaction happens. The immune system attacks the allergen with the release of a type of anitbody called immunoglobulin E or IgE. Each IgE is specific for one particular substance like oak pollen or ragweed pollen etc. IgE molecules are special because they are the only antibody that attaches to tissue cells and blood cells. When the allergen comes in contact to it's specific IgE, the cell to which the IgE is attaches, release or produce powerful chemicals like histamine which causes inflammation or swelling. These chemicals act on tissues such as those in the respiratory system causing allergy symptoms.

Some signs and symptoms of airborne allergies include:

  • Sneezing, often with a runny or clogged nose
  • Coughing and postnasal drip
  • Intching eyses, nose, and throat
  • Watery eyes
  • Dark circles under the eyes caused by increase blood flow near sinuses


Normally, foreign particles that enter the nose are washed into the throat by the nasal mucus where they are swallowed or coughed out. With allergic people, as soon as the allergen lands on the lining of the nose, histamine and other chemicals are released causing nasal passages to swell, sneezing, itching and irritation and access mucus production.

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