This chapter discusses nasal allergy, where rhinitis has been reported to reduce sleep, emotional well-being, and concentration levels, and to increase headache and malaise. Allergy is a result of a hypersensitivity of the immune response to a particular antigen. Activation of the immune system by exposure to triggering allergen causes release of inflammatory mediators and the subsequent inflammation and tissue destruction that are responsible for the symptoms of allergy. Type I hypersensitivity reactions are mediated by specific IgE antibodies to allergen, where IgE antibody exists bound to mast cells. Type III hypersensitivity reactions occur when a large number of antibody-antigen complexes accumulate in tissues. The first-line treatments for allergic rhinitis include nasal steroids and non-sedating antihistamines. Simple strategies such as limiting pollen exposure by closing windows, using an air conditioner, or incorporating a high-efficiency particulate arresting (HEPA) filter.