Understanding Hay Fever
by Beth G. Hodges, MD

Hay fever, called seasonal allergic rhinitis, is an allergic reaction to circulating pollen. It affects 20% of the United States population, similar percentages in most other developed countries. A tendency towards developing hay fever can run in families, though sensitivity to a particular allergen is person-specific. For example, a son might inherit the tendency towards allergies from his father, but the father may be allergic to dogs while the son is allergic to cats.

Hay fever occurs because the body misidentifies the allergen (i.e. pollen) as a foreign invader and releases histamine to fight it. The release of histamine results in swelling and irritation of the sinuses and nasal passages. Frequent sneezing occurs in an attempt to expel the invader from the body.

It is a common misconception that allergies develop only in childhood. In fact, allergies can develop at any stage of life. Once an allergy develops, the immune system remembers it forever, unless a process of gradual desensitization is undertaken, commonly called "allergy shots."

A specialty physician called an allergist can perform skin tests to help determine the source of a person's allergy response or blood tests can be done to identify antibodies, the body's response to a specific allergen. This process can be helpful in that the best treatment for hay fever is to avoid the cause of the allergic response. For example, someone who is allergic to pine trees may choose to live in the arid Southwestern United States, where they are less common.

Sometimes, the time of year the person experiences the allergic response is enough to isolate a cause. For example, tree allergies are usually prevalent in the spring, grass allergies in the summer, and the fall is famous for ragweed. However, mold is prevalent from spring through fall, so there can be overlap. Also, some people have allergic responses to indoor allergens, such as mildew, mold, dust mites, and pet dander, and these occur year-round.

If it is not possible to avoid the cause of the hay fever, the next step is to take an antihistamine, which decreases the body's release of histamine to the allergen. This medication does not make a person "less allergic" but simply blocks the body's natural response to the allergen, and thus, the symptoms.

Decongestants and nasal steroid sprays can also help alleviate the symptoms. As mentioned above, for those with severe responses, immunotherapy, or allergy shots, may be considered. The allergist makes up minute amounts of the allergen and this is injected under the skin of the allergic person weekly, gradually increasing the dose each time until the person becomes desensitized. Although this sounds fairly routine, injecting something to which a person is allergic directly into that person's body is dangerous and must be done with careful supervision. The desensitization process takes several years and if for any reason is stopped before finished, would have to be started all over again.

Hay fever is a common medical complaint, the symptoms of which can be transient and mild or chronic and debilitating. Treatment should be focused first on identifying and avoiding the allergen and if this is not possible, on symptom suppression.

Studies have shown that children with untreated hay fever perform more poorly in the classroom, possibly because of sleep disturbances due to inflamed and congested respiratory passages.

Published - January, 2010