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 …

Oct 15, 2025 · Key Takeaways Allergens are substances that cause the body to produce an allergic reaction. Common allergy symptoms include a runny nose, congestion, cough, and …

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.

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 …

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.

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 …

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).

Allergens are substances that trigger allergy symptoms. Many types of things can be an allergen. Allergens that affect one person may not affect other people.