An allergy is an exaggerated response of the immune system to certain foreign particles present in the environment.

What Triggers an Allergy?

The substances that cause an allergic reaction are called allergens. These are usually harmless materials that your body mistakenly identifies as dangerous invaders. Common examples include dust mites, pollen grains from flowers, animal dander (tiny scales of skin), and certain types of food like peanuts or shellfish. When these allergens enter your body, your immune system acts as if it is under attack.

The Role of Antibodies

When you are exposed to an allergen, your body produces a specific type of antibody called Immunoglobulin E (IgE). Antibodies are protective proteins produced by your immune system to fight off germs. In the case of an allergy, the IgE antibodies latch onto the allergens. This binding triggers the release of chemicals, most notably histamine and serotonin, from specific cells called mast cells.

Symptoms and Body Responses

Histamine is the main chemical responsible for the physical symptoms we notice during an allergic reaction. Because these chemicals travel through the bloodstream, they cause reactions in different parts of the body:

• Sneezing and runny nose: Caused by irritation in the nasal passages.
• Watery eyes: An attempt by the body to wash away the allergen.
• Skin rashes or hives: Red, itchy patches that appear when chemicals reach the skin.
• Difficulty breathing: This occurs if the airways become swollen, which is a serious condition.

How Doctors Diagnose Allergies

To identify the specific allergen, doctors use two primary methods. First, they inject small amounts of suspected allergens under the skin of the patient to observe any swelling or redness. This is called an allergen sensitivity test. Alternatively, they may perform a blood test to measure the level of IgE antibodies. To manage allergies, doctors often prescribe anti-histamines, adrenaline, or steroids, which work by stopping the chemical release that causes the symptoms.