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.

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 …

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 …

Sep 10, 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.

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.

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.

2 days ago · Check out national allergy map, get your local allergy outlook, track you allergies with Allergy Diary, and more features at Pollen.com

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 …

Mar 31, 2024 · An allergy is an immune response or reaction to substances that are usually not harmful. Allergies are very common. Both genes and environment play a role. If both your parents have …

Apr 1, 2025 · Allergic reactions happen when you come into contact with an allergen. Your immune system reacts by releasing histamines and other chemicals into your blood, causing symptoms that …