What causes allergic symptoms according to the passage?

Allergic symptoms are primarily caused by a malfunction in the immune system. In individuals with allergies, the immune system mistakenly identifies harmless substances, known as allergens, as threats. This triggers an inappropriate immune response, leading to the production of antibodies like immunoglobulin E (IgE). This process causes the immune system to release various chemicals, including histamines, which are responsible for the symptoms commonly associated with allergic reactions, such as sneezing, itching, and swelling. Understanding this malfunction helps in grasping why allergies occur and how the body responds to certain substances that are typically harmless.