Health encyclopaedia

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Causes of Allergies

Allergies are caused by the body’s immune system reacting to allergens as if they were harmful. The immune system does this by making antibodies to fight off the allergen. Antibodies are  special proteins made in the immune system to fight off viruses and infections that could harm us.

When the body comes into contact with an allergen, the antibody released is called Immunoglobulin E (IgE) This  antibody causes other blood cells to release more chemicals (including histamine), which together cause the symptoms of an allergic reaction. Histamine causes most of the typical symptoms that happen in allergic reaction:

• It makes muscles contract, including those in the walls of the air tubes of your lungs.
• It increases the amount of fluid that is released from small veins, so that membranes swell.
• It increases the amount of mucus produced in your nose lining and causes local itching and burning.

Atopy:

Some people are predisposed to allergy. This means they are more likely to develop an allergy because it runs in their family. If you are predisposed to an allergy, the condition is called atopy. People who are atopic are more likely to develop allergies because their body produces more IgE antibody than normal.

Although atopy is inherited, environmental factors also play a part in the development of allergic disorders. This is why not all members of a family are affected to the same extent. The amount of contact you have with allergens in your first years of life is particularly important. For example, constant exposure to cigarette smoke, house dust mites, pollens, pets and certain foods makes you more likely to become allergic to them. Air pollution, processed foods and frequent use of antibiotics all seem to make us more likely to develop allergies as well. 

There are thousands of allergens. Some of the most common include:

• House and dust mites,
• Grass and tree pollens,
• Pet skin flakes or hair,
• Fungal or mould spores,
• Food (milk, egg, wheat, soya, seafood, fruit and nuts)
• Wasp and bee stings,
• Certain medication,
• Latex , and
• Nickel, rubber, preservatives and chemical resins.
   
  

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