Allergic response produce histamines. These histamines will act on different areas of the body (eyes, throat, nose, gastrointestinal tract, skin or lungs) to produce symptoms of an allergic reaction. The allergic response is not limited to a certain amount of exposure. If the body is exposed to the allergen multiple times the immune system will react every time the allergen is present. The reason why people get allergies is not known. The allergens are not passed down through generations. It is believed if parents have allergies the child is more likely to be allergic to the same allergens. Some common symptoms include
Juniperus virginiana female), 'Goldspire' (narrow conical with yellow foliage), and 'Kobold' (dwarf). Some cultivars previously listed under this species, notably 'Skyrocket', are actually cultivars of "J. scopulorum". In the Missouri, Oklahoma and Arkansas Ozarks, eastern juniper is commonly used as a Christmas tree. The pollen is a known allergen, although not as potent as that of the related "Juniperus ashei" (Ashe juniper), which sheds pollen a month earlier. People allergic to one are usually allergic to both. "J. virginiana" sheds pollen as early as late winter and through early spring. Consequently, what begins as an allergy to Ashe juniper in the winter