What causes allergies?

An allergy is when your body is hypersensitive to a foreign substance that is normally harmless. This hypersensitivity may lead to violent reactions for the body. 

Though there are many forms of allergies Chronic Allergies are the most common forms.  Chronic means a daily, ongoing occurrence of allergies.

A person suffering from chronic allergies may develop nasal allergies and or be effected by cold air, dry air, particles present in the air and smoke  Other substances can lead to allergies.  Dust mites, animal dander, mold spores, dust and pollens are some of the common allergens. 

Allergen are harmless to most people however for the unlucky few the could lead to minimal brain dysfunction and faulty thinking, especially in children.