What are Allergies?
Allergies are hypersensitive immune responses to substances that either enter or come in contact with the body, such as pet dander, pollen or various molds.
A substance that causes an allergic reaction is called an “allergen”. Allergens can be found both outdoors and indoors.
Most allergens are harmless, that is, the majority of people are not affected by them.
If you are allergic to a substance, such as pollen, your immune system reacts to it as if it were a pathogen (a foreign harmful substance), and tries to destroy it. This over-reaction is caused by your body over-producing a specific allergen antibody called IgE.
Allergies are very common. Public health authorities estimate that about 20% of people in North America and Western Europe suffer from some degree of hay fever (allergic rhinitis, allergy to pollen).
An estimated 150 million+ Americans have an allergy.
The number of people worldwide with allergies is increasing. According to Allergy UK, about 30-40% of people have an allergy at some stage in their lives. Some years ago, this increase was only apparent in industrialized nations. However, middle-income nations are now reporting higher rates of allergies across their populations.
When a person with an allergy comes into contact with an allergen, the allergic reaction is not always immediate. The immune system gradually builds up sensitivity to the substance before overreacting to it.
The immune system needs time to recognize and remember the allergen. As it becomes sensitive to it, it starts making antibodies to attack it – this process is called sensitization, and this is where the allergen antibody IgE is produced
When the immune system reacts to an allergen, there is inflammation and irritation. Signs and symptoms depend on the type of allergen. Allergic reactions may occur in the gut (digestive system), skin, sinuses, airways, eyes, and nasal passages.
Allergies from dust, pet dander and pollen may have the following symptoms:
- Blocked or Stuffy Nose
- Itchy or Watery Eyes
- Itchy Nose
- Runny nose
- Swollen Eyes
- Nasal and Sinus Congestion
Allergies are caused by an over-sensitive immune system, specifically an over-production of the allergen antibody IgE.
The immune system of a person with an allergy reacts to the allergen as though it were a harmful pathogen – such as an undesirable bacterium, virus, fungus or toxin.
However, the allergen is not harmful. The immune system has mistakenly become oversensitive to that substance, and identified it as potentially dangerous, which it is not.
When the immune system reacts to an allergen, it releases immunoglobulin E (IgE), a type of antibody. IgE is released to destroy the allergen.
IgE causes chemicals, such as histamine, in the body to be produced and released to attack what the body mistakenly believes may be a dangerous “foreign invading substance”. These chemicals cause the allergic reaction which most people refer to as their “allergies”.
One of the chemicals released is called histamine. Histamine causes tightening of the muscles, including those in the airways and the walls of blood vessels. It also makes the lining of the nose produce more mucus.
People with allergies usually blame the allergen for their symptoms – a friend’s pet, pollen or dust mites. However, the allergens are not harmful.
The root cause of allergies is not the allergens, but the allergic person’s immune system which mistakes harmless substances for harmful ones.