Hay Fever, form of seasonal rhinitis caused by allergy to pollens. Its symptoms are intense seizures of sneezing; inflammation of nose and eye membranes; and wheezing. Hay fever occurs annually at the same season. It is a reaction to inhalation of airborne pollens to which an individual is sensitive. Persons with a family history of hay fever may inherit a tendency to react, not to specific allergens, but to those to which they are exposed. Perhaps 8 to 10 percent of the U.S. population is affected.
A doctor may determine the sensitizing agent or agents by scratching the skin of the patient and applying various pollens. The pollens to which the patient is allergic will produce a wheal-and-flare reaction. Because hay fever involves an antigen-antibody reaction in which histamine in the body is released and irritates blood vessels and glands, some anti-histaminic agents may furnish relief. Long-term therapy involves a series of injections of pollen extracts before the pollen season begins; repeated annually, these relieve 75 percent of cases.