Allergy & Immunity, When the Protector Becomes Oversensitive

Play to listen

Allergy & Immunity, When the Protector
Becomes Oversensitive


The immune system is an extraordinary internal defense force. Its primary task is simple yet crucial: distinguishing between "friend" (the body's own cells) and "foe" (viruses, bacteria, or parasites). However, this sophisticated system occasionally suffers from a case of mistaken identity. This is what we commonly know as an allergy.

1. How Does the Immune System Work?
Under normal conditions, the immune system operates through the coordination of white blood cells (such as T and B lymphocytes) and antibodies. When a real threat enters the body, the system produces antibodies to neutralize it.

In the case of allergies, the immune system experiences hypersensitivity. It perceives substance that are actually harmless—such as pollen, cat dander, or peanuts—as deadly threats.

2. The Mechanism of an Allergic Reaction
The allergic process typically occurs in two main stages:
  1. Sensitization: Upon the first exposure to an allergen, the body produces a specific type of antibody called Immunoglobulin E (IgE). These antibodies attach themselves to mast cells (cells that store histamine).
  2. Allergic Reaction: When exposed again, the allergen binds to the IgE on the mast cells. This triggers the release of histamine and other chemicals into the bloodstream.
The biochemical process can be simplified as follows:
Allergen + IgE (on Mast Cells) -> Histamine Release -> Allergic Symptoms

3. Common Types of Allergens
Allergens can enter the body through various routes:
  • Inhalants: Dust mites, pollen, mold, and pet dander.
  • Ingestants: Foods (milk, eggs, nuts, seafood).
  • Skin Contact: Metals (nickel), cosmetic chemicals, or latex.
  • Injections: Medications (such as penicillin) or insect stings.
4. Symptoms: From Mild to Fatal
Allergy symptoms depend largely on where the histamine is released:
  • Nose & Eyes: Sneezing, itching, and watery eyes (Allergic Rhinitis).
  • Lungs: Shortness of breath and wheezing (Asthma).
  • Skin: Rashes, hives (Urticaria), or eczema.
  • Systemic: Anaphylaxis, a life-threatening emergency involving a drastic drop in blood pressure and narrowing of the airways.
5. The Link Between Immunity and Environment
There is a compelling theory known as the "Hygiene Hypothesis." It suggests that environments that are "too clean" during childhood may leave the immune system "under-trained." Because there are no real germs to fight, the immune system becomes hypersensitive and begins attacking harmless substances, leading to the rise of allergies in modern society.

Data Sources & References
This article is based on general immunological principles and data from leading health organizations:
  • World Allergy Organization (WAO): White Book on Allergy – Global allergy prevalence data.
  • Mayo Clinic: Allergies: Symptoms & Causes – Biological mechanisms of histamine and IgE.
  • Journal of Allergy and Clinical Immunology: Studies regarding the "Hygiene Hypothesis" and immune system development.
  • American Academy of Allergy, Asthma & Immunology (AAAAI): Clinical guidelines for managing hypersensitivity.
Alergi & Imunitas