Your Immune System
An allergic response to a harmless substance, such as pollen, occurs when the immune system mistakenly identifies it as an enemy. The result is repeated sneezing, a blocked nose, itchy eyes, coughing, and rhinorrhea – or runny nose.
When Sensitivity Becomes Allergen
If you are allergic to pollen, you most likely did not have symptoms when you were initially exposed; however, your immune system decided to defend you against the perceived threat. This process is called sensitization. During the sensitization process, your symptoms increased little by little.
When does sensitivity become an allergy? It is based on what is happening inside your body. When your immune system has created a complete defense mechanism intended to destroy the allergen, you have allergic rhinitis. Inflammation is your body’s way of responding to stress, and allergic rhinitis is an inflammatory condition.
If you have developed sensitivity to certain substances, you may not have severe symptoms, but your immune system is laying the groundwork for full-blown allergic reactions in the future. Then one day you have allergic rhinitis. At this point, when your immune system mounts its defense against an allergen, numerous immune cells circulate throughout your body, including eosinophils, which are always found in the bloodstream of people with allergic rhinitis.
When you have allergic rhinitis, your body tries to defend you against an allergen. So if you are allergic to pollen, going outdoors into a field of wildflowers on a beautiful spring day will trigger a series of events in your immune system that cause allergic symptoms. These symptoms will continue unabated until you are no longer exposed to the allergen. In fact, sometimes they may continue for several hours after exposure, because your immune cells are continuing to work to protect your body from the "dangerous invader" even when the perceived threat is no longer present.
