Final answer:
Common allergens provoke an immune response characterized by the production of IgE antibodies upon first exposure. These antibodies then cause the release of histamine and other chemicals during subsequent exposures, leading to allergic reactions. Allergens include substances like pollen, dust, and certain foods.
Step-by-step explanation:
Common allergens are small proteins inhaled in particulate form that stimulate an immune response. An allergy is essentially an antibody-mediated immune reaction that occurs within minutes of being exposed to an allergen, a usually harmless antigen.
In an allergy, the person's immune system overreacts to an external substance that is typically considered non-threatening.
Upon initial exposure to an allergen, a sensitization process occurs, involving the production of IgE antibodies by the immune system.
When a person is re-exposed to the same allergen, these antibodies bind to it and signal immune cells like mast cells to release histamine and other chemicals, causing symptoms such as sneezing, itchy eyes, and in severe cases, anaphylactic shock.
The allergens can include various substances, such as pollen, dust mites, or certain foods like peanuts.