Hay fever is described as a seasonal, abnormal response to external irritants in the mucous membranes of the nose and upper respiratory tract. Another term for hay fever is pollinosis, an acute seasonal form of allergic rhinitis (see Diagnostic Code: 6522 Allergic or vasomotor rhinitis).

The incidence of hay fever is generally stimulated by seasonal wind-borne pollens occurring in the spring, summer, and fall. The spring-type pollen comes from oak, elm, maple, juniper, olive and birch trees. The summer-type pollen comes from grass and weeds; and the fall-type pollen comes from ragweed. There are differences in geographical regions, and, occasionally, airborne fungal spores may cause hay fever.

When the pollen season begins, these signs and symptoms begin gradually or abruptly, and usually include: itching of the nose, eyes, roof of the mouth and pharynx. There is sneezing, tearing, and a clear, watery nasal discharge. In addition, frontal headaches and irritability may occur, along with swollen nasal membranes and reddened conjunctiva. Wheezing and coughing develop as the season continues.

Customary diagnostic measures include: history and physical examination; testing of nasal secretions for eosinophils; and skin tests to determine the offending pollens.

Treatment usually starts with advising the patient to avoid the causative allergen. Medications commonly used for treatment include: oral antihistamines; topical nasal sprays containing either antihistamine or glucocorticoid medications; and desensitization by allergy injections.

When systemic glucocorticoids become necessary, or topical treatment has become unsatisfactory, then immunotherapy is started after pollen season ends to prepare for the next season. Patients on high blood pressure medication must be cautioned about usage of decongestant preparations which have a tendency to raise the blood pressure.

"Seasonal and other acute allergic manifestations subsiding on the absence of or removal of the allergen are generally to be regarded as acute diseases, healing without residuals." 38 CFR 3.380 [Diseases of allergic etiology]