Allergy Basics: What Happens During an Allergic Reaction?

An allergic reaction occurs when your immune system overreacts to a foreign substance, known as an allergen. This happens when your body mistakes the allergen as harmful and produces antibodies to fight it off. When you come into contact with the allergen again, these antibodies bind to it, triggering the release of chemicals like histamine. These chemicals cause the symptoms associated with an allergic reaction.

Here's a step-by-step breakdown of what happens during an allergic reaction:

1. Exposure: You come into contact with an allergen, such as pollen, dust mites, pet dander, or certain foods.

2. Immune System Recognition: Your immune system recognizes the allergen as foreign and potentially harmful.

3. Antibody Production: B cells, a type of white blood cell, produce antibodies called immunoglobulin E (IgE) specific to the allergen.

4. Sensitization: These IgE antibodies bind to receptors on mast cells, which are immune cells found in tissues throughout the body, especially those lining the nose, lungs, skin, and gut. This process is called sensitization.

5. Re-exposure and Allergen Binding: When you encounter the allergen again, it binds to the IgE antibodies attached to the mast cells.

6. Histamine Release: This binding triggers the release of histamine and other inflammatory mediators from the mast cells. These chemicals cause the symptoms associated with an allergic reaction.

7. Symptoms: Depending on the location of the allergen exposure and the person's sensitivity, symptoms may include sneezing, a runny nose, watery eyes, congestion, skin rashes, hives, difficulty breathing, or even a life-threatening condition called anaphylaxis.

8. Resolution: In most cases, mild allergic reactions resolve on their own over time. However, severe reactions may require immediate medical attention and treatment with antihistamines, corticosteroids, or epinephrine (adrenaline) in case of anaphylaxis.

It's important to note that not everyone who is exposed to an allergen will develop an allergic reaction. Some individuals may become sensitized but not develop symptoms, while others may only react to specific amounts or concentrations of the allergen. The severity of an allergic reaction can also vary from person to person.

If you suspect you have an allergy or experience symptoms after coming into contact with a particular substance, it's recommended to consult an allergist for proper diagnosis, allergy testing, and recommendations for managing your allergies effectively.