An allergy occurs when the body reacts to foreign particles it can't tolerate. These particles, such as tree pollen or dust mites, are called antigens, or allergens, and are normally harmless. But the immune system of a person with allergies views the allergens as harmful.
Following the body’s first contact with an allergen, white blood cells produce antibodies that prepare the immune system for the same allergen the next time it enters the body. Antibodies attach themselves to cells such as basophils and mast cells.
Later contact with even a small amount of the allergen triggers the cells to release chemicals such as leukotrienes, prostaglandins, and histamine. When these chemicals are released, they attach to the receptors of nearby cells. The binding causes swelling of nasal blood vessels and inflammation of membranes.
This results in common allergy symptoms such as: • sneezing • itchiness • watery nose • and congestion
Normally to reduce inflammation, the brain signals the adrenal glands to produce a hormone called cortisol. Cortisol works against allergens by acting on receptors in the cytoplasm of various cells. Once bound, cortisol-receptor complex enters into the nucleus. There it binds to the DNA and prevents the creation of proteins responsible for the release of inflammatory chemicals. As a result, when the allergen binds to the antibodies on the cell, the cell is not triggered to release inflammatory chemicals.
Sometimes cortisol is not able to control the immune system response. In this case, nasal corticosteroids, synthetically-produced hormones similar to cortisol, may be prescribed. When inhaled, they bind to receptors and the complex works in the same way as cortisol. Therefore, when the allergen binds to the antibodies on the cell, the inflammatory chemicals are not released. As a result, the immune system’s response is decreased and symptoms are reduced.
While effective, corticosteroids are not right for everyone and can cause minor as well as serious side effects, so a corticosteroid therapy should only be started under the care and guidance of a physician.