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. These allergens can range from pollen and dust mites to certain foods and insect stings. When exposed to an allergen, the body produces antibodies that bind to the allergen and signal the release of histamine and other chemicals. These chemicals cause the symptoms associated with an allergic reaction. Here is a breakdown of the key steps involved:

1. Allergen Exposure:

- An allergen enters the body through contact with the skin, ingestion, inhalation, or injection (in the case of insect stings).

2. Antibody Production:

- Your immune system recognizes the allergen as foreign and produces antibodies called immunoglobulin E (IgE). These IgE antibodies bind to specific cells called mast cells and basophils.

3. Mast Cell Activation:

- Upon re-exposure to the same allergen, the allergen binds to the IgE antibodies on the mast cells. This triggers the release of histamine and other chemical mediators.

4. Histamine and Chemical Release:

- Histamine causes blood vessels to dilate and become leaky, leading to tissue swelling and fluid buildup. Other chemicals released, such as leukotrienes, also contribute to the symptoms of an allergic reaction.

5. Allergic Symptoms:

- The symptoms experienced during an allergic reaction depend on the allergen and the individual's sensitivity. Common symptoms include:

- Sneezing, itchy, and watery eyes (allergic rhinitis)

- Itchy skin, hives, and rashes (urticaria)

- Difficulty breathing, wheezing, and coughing (asthma)

- Swelling of the lips, tongue, and throat (angioedema)

- Nausea, vomiting, and abdominal pain

- In severe cases, anaphylaxis can occur, leading to a drop in blood pressure and potentially life-threatening symptoms.

It is important to note that allergic reactions can vary in intensity and severity from person to person. If you experience symptoms of an allergic reaction, seeking medical attention, especially for severe reactions, is crucial. Knowing your triggers and carrying an epinephrine auto-injector (EpiPen) if prescribed by your doctor can help manage allergic reactions effectively.