Play to listen
What is an Allergy?
A Comprehensive Explanation
from the Immune System Perspective
 |
| Switch to Indonesian |
Have you ever wondered why someone’s body reacts violently to a single peanut or a bit of dust, while others remain perfectly fine? In medical terms, this isn't just a simple physical reaction—it is a major "misunderstanding" occurring within our body’s defense system.
Understanding the Essence of Allergies
An allergy is a hypersensitivity reaction of the immune system to foreign substances that are usually harmless to most people. These trigger substances are known as allergens.
Under normal conditions, the immune system is responsible for attacking real threats like viruses, bacteria, or parasites. However, in an allergic individual, the immune system mistakenly identifies neutral substances—such as pollen, cat dander, or food proteins—as dangerous enemies that must be destroyed.
Immune Mechanism,
How the Body "Misunderstands"
The occurrence of an allergy involves complex communication between immune cells, taking place in two main stages:
1. The Sensitization Phase (The Introduction)
When the body first encounters an allergen, the immune system does not immediately cause itching or sneezing. Instead, white blood cells (B lymphocytes) produce specific antibodies called Immunoglobulin E (IgE). These IgE antibodies then attach themselves to the surface of mast cells (chemical-storing cells in body tissues). At this stage, your body is on "high alert" for that specific substance.
2. The Reactivation Phase (The Counter-Attack)
When the body is re-exposed to the same allergen, the substance binds directly to the IgE already waiting on the mast cells. This binding causes the mast cells to "degranulate" or burst, releasing aggressive chemicals called Histamine.
3. The Role of Histamine
Histamine is the primary culprit behind the uncomfortable symptoms you experience. Histamine causes:
- Blood vessels to dilate (causing redness).
- Increased mucus production (runny/stuffy nose).
- Stimulation of itch nerves.
- Contraction of smooth muscles in the lungs (causing shortness of breath).
Symptoms Based on Reaction Site
Allergy symptoms depend heavily on where the most histamine is released:
- Respiratory Tract: Sneezing, itchy nose, and asthma.
- Skin: Red rashes, hives (urticaria), or swelling.
- Eyes: Watery, red, and burning sensation.
- Digestive System: Bloating, vomiting, or diarrhea after consuming a trigger.
Crucial Note: The most severe condition is called Anaphylaxis. This is a medical emergency where the immune system releases a massive "chemical bomb" throughout the body, which can lead to a drastic drop in blood pressure and airway obstruction.
Common Allergens Around Us
| Category | Examples of Allergens |
- Airborne | Dust mites, pollen, pet dander, mold.
- Food | Cow's milk, eggs, peanuts, seafood, wheat.
- Others | Bee sting venom, latex, and certain medications (such as penicillin).
✓ Allergies are proof of how sophisticated the human immune system is, yet sometimes it acts overprotectively. Understanding that the real enemy is not the dust or the food itself, but rather our own IgE antibody reaction, helps us handle this condition more wisely through prevention and proper treatment.
Data Sources & Article References:
- Mayo Clinic (2024). Allergies: Symptoms, Causes, and Risk Factors.
- World Allergy Organization (WAO). White Book on Allergy: Global Perspective on Allergic Diseases.
- American Academy of Allergy, Asthma & Immunology (AAAAI). The Immune System and the Allergic Response.
- Janeway's Immunobiology. Section: IgE-mediated Immune Responses and Allergic Reactions.
Alergi&Imunitas