Hay fever
Hay fever, also known as seasonal allergic rhinitis, is a common allergic disorder affecting about 10 percent of the population. It is primarily triggered by an immune response to pollen grains, particularly from trees, grasses, and ragweed. When a person who is genetically predisposed to allergies is first exposed to pollen, their immune system becomes sensitized. On subsequent exposures, this leads to the release of histamine and other substances, resulting in symptoms like itchy eyes and nose, sneezing, and increased mucus production.
The condition is predominantly seasonal, with symptoms flaring up during periods of high pollen count. Effective management typically includes avoidance of allergens, although complete avoidance can be challenging. Common treatments involve desensitization, where patients receive gradual exposure to increasing amounts of the allergen, and medications such as antihistamines that alleviate symptoms. While current treatments primarily focus on symptom relief, future advancements may target underlying allergic responses with fewer side effects. Understanding hay fever can help individuals recognize their symptoms and explore appropriate treatment options.
Hay fever
ALSO KNOWN AS: Seasonal allergic rhinitis
ANATOMY OR SYSTEM AFFECTED: Eyes, immune system, lungs, lymphatic system, nose, respiratory system, throat
DEFINITION: A damaging immune response to otherwise harmless foreign substances such as pollen grains and mold spores
CAUSES: Allergic reaction to pollen
SYMPTOMS: Itchy eyes and nose, sneezing
DURATION: Seasonal
TREATMENTS: Avoidance of allergens, desensitization, antihistamines
Causes and Symptoms
Allergic rhinitis, popularly known as hay fever, represents the most common allergic disorder, affecting approximately 10 percent of the population; the most common source of the allergy is wind-dispersed pollen. These tiny grains are produced in phenomenal numbers to ensure transfer of the pollen (which contains the plant’s sperm) to other flowers of the same plant species. Trees, grasses, and certain forbs (especially the ragweeds) are the most common culprits. The first time that a susceptible person is exposed, the pollen acts to sensitize the immune system. On second and subsequent exposures, the pollen triggers an allergic response.
This response is triggered by the formation of a specific class of known as IgE against the proteins on the pollen grains (generally called antigens and in this case called allergens). Immunoglobulin E (IgE) attaches to tissue cells called mast cells by one end and to the pollen grains at the other end. This attachment causes the to release defensive substances, the best known of which is histamine. These substances cause increased permeability of and the production and release of mucous and watery substances from the nasal passages and eyes. Itching and sneezing accompany the release. The tendency to produce IgE against pollen allergens is an inherited trait; persons with one or both parents who have to certain substances are more likely to exhibit the same allergies than persons whose parents do not exhibit such responses.
Treatment and Therapy
It is generally agreed that avoidance of the is the most effective therapy for hay fever. Staying inside a building with air conditioning or well-filtered air during the worst allergy season helps. However, avoiding an allergen completely, such as ragweed pollen during ragweed’s flowering season, is essentially impossible.
The most common treatments employed are desensitization and drugs. Desensitization involves a series of injections of slowly increasing concentrations of the allergen, in the hope of turning the patient’s from the production of IgE to the production of G (IgG), which does not trigger the mast cells. Drugs such as antihistamines, which block the action or the release of histamine and the other substances released by mast cells, are commonly recommended, either in prescription strength or over the counter. Steroid and decongestant sprays have also been successful in relieving the symptoms of hay fever in some individuals.
Perspective and Prospects
For many persons, long-term avoidance of allergens such as pollen may be difficult. Current drugs such as are directed primarily at relieving symptoms without removing the cause: the binding of IgE to the allergen. Future drugs may address the variety of steps involved in the allergic response while causing fewer side effects such as sleepiness. Other treatments may involve augmentation of IgG production in response to with the allergen, since IgG competes with IgE in binding to the allergen.
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