Asthma is one of our nation's most common chronic health conditions. Many substances can aggravate allergies or increase the severity of asthma symptoms in individuals who are sensitive to these allergens or irritants.

Sometimes it's hard to know whether you're suffering from allergies or a string of colds. Their symptoms – like sneezing, coughing and a runny nose – are similar. If you have these symptoms every spring or fall, or all through the growing season, it's a good bet you've got seasonal allergies, or hay fever. Doctors call this type of allergy "seasonal allergic rhinitis". Whatever its name, it can make you absolutely miserable.

The National Institute of Allergy and Infectious Diseases (NIAID) estimates that the number of people suffering from allergic rhinitis may be as high as 35 million. Allergic rhinitis may not seem dangerous in itself, but it can play a role in other diseases like asthma, a chronic and potentially fatal lung disease affecting approximately 15 million Americans, and sinusitis, an infection in the hollow air spaces of the skull surrounding the nose that affects approximately 38 million Americans.

There is no cure for allergy, but there are ways to control its symptoms and, hopefully, to prevent it from triggering more serious conditions like asthma and sinusitis.

If you do have allergic rhinitis, you and your doctor have many options. The first, and most obvious, is to avoid the allergens you react to. This is not as simple as it might seem. Some people think that they can just move to a place where the offending pollen doesn't grow. This drastic measure may provide temporary relief, but people who have an allergy to one thing tend to develop allergies to others as well, and may soon find themselves in the same situation.

There are some simple things you can do. Sunny, dry, windy days can be especially troublesome for people with pollen allergies, so try to stay indoors on those days with the windows closed and the air conditioner on. Some people take vacations at the height of the expected pollination period and choose a location where they won't get much exposure; the seashore, for example, is a good place for many people with pollen allergies.

If avoidance doesn't work for you, allergy symptoms can often be controlled with medications. Antihistamines are usually the first line of defense. As you might expect from the name, an antihistamine counters the effects of histamine, which is one of the chemicals released by mast cells and basophils that cause allergy symptoms. Some antihistamines can cause drowsiness and loss of alertness and coordination. During the last few years, however, antihistamines that cause fewer of these side effects have become available.