Allergies are the result of an immune response - HSC - SSCE Biology - Question 13 - 2006 - Paper 1

The immune response that leads to allergies is primarily triggered by antigens. Antigens are substances that the immune system recognizes as foreign, such as pollen, dust mites, or certain foods. When these antigens enter the body, they can provoke an allergic reaction from the immune system, resulting in symptoms such as sneezing, itching, or swelling.