Allergies can be defined as inappropriate immune system reactions to a foreign substance entering body. Allergies are kind of diseases of immune system works to react to certain substances called allergens. Normally when a person is exposed to a harmless substance such as pollen, causes the body natural immune system to respond as if the substance is harmful. Some allergies are inherited from their parents or can be gained in environmental exposure. There are several common allergen exposures like mold, animal dander, pollen, dust mites, and many others.
If you have an allergy and the allergen (or allergy trigger) enter your body, there must be an allergic reaction. An allergic reaction is a hypersensitivity reaction, which is the result of interaction between our immune system with the allergen itself. The consequence is a release of inflammatory reactions chemicals that can manifest in the symptoms like swelling of the body tissues, cause itching, congestion of blood vessels, increased secretions and bronchial spasms. If the allergen is eaten, it cause allergic reactions occur mainly in the mouth, stomach and intestine. If the allergen is exposed in the air, mostly the allergic reactions will appear in eye, nose and lungs.
There are certain types of allergies that are likely to occur in some part of our life for the first time. They are and age:
Infant: Atopic dermatitis, food allergies (allergies to milk, egg, nuts)
Early childhood: Asthma (allergies to house dust mite, pets)
Teenagers: Allergic rhinitis (most common triggers are grass and tree pollens)
Early adulthood: Urticaria, angio-oedema (drugs and aspirin intolerance)
Adulthood: Allergy to venom (bee sting, wasp) and nasal polyps allergy
