Seasonal allergies are allergic reactions to airborne substances that appear during certain times of the year. The best-known of these are reactions to trees, weeds, and grass pollens. Seasonal allergies are manifested through a runny nose, itchy skin, watery eyes, and sneezing.
You might have heard of these allergies referred to as “hay fever.” Hay fever is not actually caused by the gathering of hay. Rather, it refers to symptoms that tend to develop at the same time that hay is harvested.
Seasonal allergies are very common during spring and fall, but they tend to die down a bit during summer and winter when the temperatures reach extremes. Seasonal allergies typically affect the membrane that lines the nose, causing inflammation that results in allergic rhinitis. When allergies lead to inflammation of eyelid membranes and whites of the eyes, they cause allergic conjunctivitis (also known as pink eye).
There are different types of allergy-causing pollens depending on the season. During spring, oak, maple, elm, alder, juniper, birch, and olive trees produce an onslaught of pollens. During summer, different types of grasses and weeds generate pollens. During fall, ragweed is one of the biggest offenders.
Various regions of the country play host to different pollens. Mountain cedar is the main source of tree pollen from December to March in the western part of the U.S. In the Southwest, grasses pollinate for many months of the year.
People may react to one or more types of pollen, causing allergies that endure through multiple seasons. They may also have sensitivities to other environmental sources such as mold. Mold spores tend to be airborne from spring through fall.
The diagnosis of seasonal allergies is usually based on a person’s symptoms as well as the circumstances in which the allergies occur. If the allergies only develop during certain times of the year, there is a great likelihood that they are seasonal. If they happen year-round, a person may be allergic to a cat or dog, mold in the home, food, or house dust. An allergy doctor may administer a skin scratch test to help determine the source of a patient’s symptoms.
Seasonal allergies may be treated by corticosteroid nasal sprays or antihistamine medications. They can also be treated with sublingual immunotherapy (allergy drops) or allergy shots, which address the underlying allergy (not just its symptoms) for lasting results.