Immune response of the upper airways triggered by inhaled airborne allergens

Seasonal allergic rhinitis — an immunoglobulin (Ig) E-mediated type I hypersensitivity response to an environmental antigen (allergen) in a genetically susceptible person

Perennial rhinitis — inhaled allergens provoke antigen responses, producing signs and symptoms year-round

Affects more than 20 million Americans

Most prevalent in young children and adolescents

The body’s immune system overresponds to common allergens in the nose.

Antibodies attach to mast cells, which release several chemicals, including histamine, and cause dilation of blood vessels, skin redness, swollen membranes in the nose, and mucous production.