What are allergic reactions like red, itchy eyes primarily caused by?

Allergic reactions, such as red, itchy eyes, are primarily caused by the release of histamines in the body. When an allergen, which might be pollen, pet dander, or dust mites, enters the body, the immune system mistakenly identifies it as harmful. In response, it triggers the release of histamines from specialized cells called mast cells. Histamines are chemicals that play a major role in the inflammatory response, leading to the symptoms commonly associated with allergies, including redness, itching, and swelling of the eyes.

While antigens are the actual substances that provoke the immune response, it is the histamines released in reaction to these antigens that cause the immediate symptoms experienced during an allergic reaction. Enzymes are proteins that catalyze biochemical reactions and aren't directly involved in allergic responses. Aspirin, while it has anti-inflammatory properties, is not a causative factor for allergic reactions like histamines are. Understanding the role of histamines can help in managing and alleviating symptoms associated with allergies effectively.