An allergy is the overreaction of the immune system to something that’s harmless. Allergic rhinitis is irritation and swelling in the nose. A chain of events starts when allergens are breathed in from the air. The most common are from grasses, trees, weeds, or animals.
Once in the nose, mast cells release histamine. This causes swelling in the blood vessels and mucous membranes in the lining of the nose. A reaction can happen quickly and involves:
Allergic rhinitis. Merck Manual Professional Version website. Available at: https://www.merckmanuals.com/professional/immunology-allergic-disorders/allergic,-autoimmune,-and-other-hypersensitivity-disorders/allergic-rhinitis. Updated January 2018. Accessed October 15, 2018.
Last reviewed September 2018 by
EBSCO Medical Review Board Marcin Chwistek, MD
Last Updated: 10/15/2018
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