When an allergen enters the body of an individual that is predisposed to allergies, it triggers an immune reaction and the production of antibodies. These allergen antibodies migrate to mast cells lining the …

Sep 22, 2025 · Food allergies occur when the body's immune system reacts to certain proteins in food. Food allergic reactions vary in severity from mild symptoms involving hives and lip swelling to severe,...

Oct 15, 2025 · When you develop an allergic reaction to a substance, your body treats that substance (allergen) as a threat. Your body then produces an immune response against the allergen.

Aug 24, 2024 · Allergies happen when the immune system reacts to a foreign substance that gets inside the body. These substances are known as allergens. They include pollen, bee venom and pet …

Jan 1, 2025 · As a result, the immune system reacts by making a type of antibody called immunoglobulin E (IgE) to defend against the allergen. This reaction leads to allergy symptoms.

Apr 3, 2025 · Overview The type of allergic reaction and its symptoms depend on the allergen and whether you inhaled it, ate it or touched it.

Allergens may be naturally occurring or of synthetic origin and include pollen, mold spores, dust, lint, animal dander, insect debris, foods, blood serum, and drugs.

An allergen is a usually harmless substance capable of triggering a response that starts in the immune system and results in an allergic reaction. For instance, if you have an allergy to pollen, your immune …

Jun 5, 2025 · How a person reacts to an allergen depends on how they come in contact with it. In many people, allergic reactions occur on the skin and in the airways and mucous membranes.

Nov 20, 2023 · An allergen is a foreign substance that's not harmful to most people, such as pollen or pet dander (skin cells from animals with fur or feathers).