By the time her daughter, Brooke, was 18 months old, Nancy Sander of Fairfax, Va., had discovered the child was allergic to much of the environment around her. Her eyes watered and her nose ran constantly. Worse yet, her allergy symptoms triggered frightening asthma attacks.

Now a 19-year-old college student, Brooke has her dorm room decked out with an air cleaner, dust mite-proof casings on the pillows and mattresses, a stash of prescription eye drops, nose sprays, and antihistamines, and a sympathetic roommate who does the vacuuming (which kicks up the dust that triggers her allergies).

"I realize she's not your typical college student," says Sander, "but she knows her quality of life is better if she does these things. Rather than hide indoors all spring, she increases her medication as needed. She washes her hair every day to keep the allergens out of it, takes her medication before she has symptoms, and she gets out there and enjoys life."

About 26 million Americans endure chronic seasonal allergies, while the number of people with milder symptoms may be as high as 40 million, according to the National Center for Health Statistics. One study puts the annual costs of "hay fever," as it's commonly called, at $2.4 million for medications and another $1.1 billion in doctors' bills.

For most people, allergies to plants that bloom in the spring and fall are merely annoying. For those with asthma or severe allergic reactions, however, these allergies may be life-threatening.

"It's better to get good treatment than to let it go," says William Storms, M.D., an allergist and professor of medicine at the University of Colorado Health Sciences Center in Denver. "We have learned a few things about this disease. First, it does affect a patient's quality of life--productivity, educational performance. Second, it may lead to secondary diseases such as otitis media [ear infections], sinus infections, and asthma."

Spring is traditionally the main season when allergies blossom because of new growth on trees and weeds. But fall, with a whole different set of blooming plants as well as leaf mold, is a close second. In addition, people who are allergic to pollens are also often sensitive to dust mites (microscopic insects that feed on human skin cells), animal dander (tiny skin flakes shed by animals), and molds, which lurk indoors in any season.

The Food and Drug Administration regulates medications and biological products that offer allergy relief. Combined with a number of strategies to minimize a person's contact with allergens, these can make life bearable for even the worst allergy sufferer.

What Is an Allergy?

An allergy is the body's hypersensitivity to substances in the environment. Allergic reactions range from mild itching, sneezing or eczema (inflamed, itchy skin), to severe hives, hay fever, wheezing, and shortness of breath. An extreme allergic reaction can result in anaphylactic shock, a life-threatening situation in which a person's airway swells shut and blood pressure drops.

Scientists believe allergies originated millions of years ago as a way for the human body to rid itself of parasites and invading worms. The body fights these and other invaders by producing an antibody called immunoglobulin E (IgE for short) in the intestines and lungs. Without modern parasites to fight, IgE reacts to other foreign substances in the body. IgE triggers immune cells to release a number of chemicals, one of which is histamine. Histamine produces hives, watery eyes, sneezing, and itching. The more a person is exposed to allergens, the more the body produces IgE; hence, allergies often get worse with age.

The Nose Knows

The most common symptom of seasonal allergies is allergic rhinitis, otherwise known as hay fever. Symptoms of allergic rhinitis closely mimic those of the common cold.

But there are differences. A cold runs its course in 7 to 10 days. Allergic rhinitis can drag on for weeks or months. Despite its nickname, "hay fever" does not cause fever. With a cold, nasal discharge may be thick and yellow. In allergies, it is generally thin and clear. An allergy is often accompanied by eye, skin or mouth itchiness and can often be traced to a specific trigger.

The first step in handling chronic allergies is a visit to an allergist. The doctor will begin by taking a detailed medical history. From that, he or she can establish a list of suspected allergens. To confirm the diagnosis or figure out puzzling allergy symptoms, the doctor may order an allergy skin test.

With this test the practitioner makes a series of punctures, each containing a small amount of one suspect allergen in solution, in a grid pattern across the surface of the patient's back. If the patient is allergic to any of the allergens, a raised red spot like a hive, called a "wheal and flare," will appear after about 20 minutes, at that site.

Depending on the patient's history, a person may be tested for as few as six allergens or as many as 80. Beware of physicians who suggest testing for 200 to 300 allergens, says Berrilyn Ferguson, M.D., an associate professor and otolaryngologist (ear, nose and throat doctor) at the University of Pittsburgh School of Medicine. At that quantity, the skin may react to everything and the test will be useless.

A more sensitive test--the intradermal test--works by injecting a drop of extract into the skin. "The intradermal test is advisable if the puncture test is negative, to avoid a serious overdose reaction," says Paul Turkeltaub, M.D., director of the division of allergenic products and parasitology in FDA's Center for Biologics Evaluation and Research.

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Treating the Symptoms

Once the causes and severity of the patient's allergies are determined, the doctor can prescribe a treatment plan. The first, most obvious, step is to avoid the allergen. (See "Keep It Clean.")

The next step in treating allergies is medication. Antihistamines, which interfere with the effect of histamine, are often prescribed. A major side effect of antihistamines is drowsiness, and some types produce more than others. The term "nonsedating" antihistamine is widely used to describe some prescription drugs, but it is not 100 percent accurate and is not a term used by FDA.

"It's really a matter of degrees," says Peter Honig, M.D., a medical officer in FDA's division of pulmonary drug products in the Center for Drug Evaluation and Research. "All the antihistamines produce drowsiness in patients, but some do more so than others." Benadryl (diphenhydramine hydrochloride), for example, is a common brand name oral antihistamine available without a prescription. It is well known to cause drowsiness in about half of people who take it. For those people, it's best taken at night. Two prescription antihistamines that have less sedation are Allegra (fexofenadine) and Claritin (loratidine).

Among nose sprays, there is Astelin (axzelastine hydrochloride), an antihistamine. Other nasal sprays contain steroids to combat congestion. These include Beconase and Vancenase (both contain beclomethasone dipropionate), Flonase (fluticasone propionate), Nasalide (flunisolide), and Nasacort (triamcinolone acetonide). The drawback to these medications is that they may take a week or so to be maximally effective and can sting and even damage the nasal septum (the soft bony division in the middle of the nose) if the spray is directed at it. Tell your doctor if you have any bloody discharge while using these sprays.

Less stinging but still helpful is the nasal spray Nasalcrom (cromolyn sodium). This nasal spray helps turn off the allergic process in the nose before it starts. It must be taken more often than a nasal steroid. Doctors often recommend this for children because it is extremely safe and it is available without a prescription.

Don't be tempted to treat an allergy with an over-the-counter decongestant nasal spray for more than three days. After a few days of use you may get a "rebound" effect, and your nose may become even more congested than before. These drugs are more useful for short-term use to relieve nasal congestion associated with a cold.

Allergy Shots

What should you do if you've tried every drug in the pharmacy and still sneeze from January to December? Allergy shots, also known as immunotherapy, can offer long-lasting relief for many people.

Getting allergy shots is a long process. Over the span of three to five years, the allergy patient receives a small injection of the offending allergens usually twice a week at first, then less often with larger doses as time goes by. These small doses desensitize the body's immune system to each allergen. After at least six months to a year, the sneezing, itching and hives may begin to subside. After about five years, it's possible for many to stop the shots completely.

"I am more productive, less irritable, and less fatigued since taking allergy shots," says Knoxville, Tenn., resident Beth Crawford, who is allergic to every tree, grass and pollen outdoors, plus dust mites, mold and animal dander indoors. Her allergies occur year-round and have plagued her since childhood.

"Now I have more confidence. I don't have to worry about whether I'm going to have a sneezing attack in public," she says. A clinical social worker, Crawford's job requires occasional public speaking; in addition, she sings in her church's choir. "Now I can sing or give a speech without worrying. I know this sounds silly, but I can get ready in the morning much more quickly because I don't have to spend 30 minutes sneezing. And my husband says we have a substantial savings in Kleenex!"

About a third of patients who get allergy shots are cured after treatment, another third have a partial relapse, and the rest will relapse completely. Those not cured may be helped by resuming the shots.

Another approach to allergy shots is called "rush immunotherapy." Patients spend several days receiving repeated shots to desensitize them against allergens. They then go on the maintenance schedule earlier. Studies have suggested rush immunotherapy can be at least somewhat effective under certain circumstances, but more study is needed to show widespread safety and effectiveness. Currently, no allergen extracts are approved by FDA for this approach.

In the Nose, Not the Head

Allergies can certainly be life-threatening, but for most people they are merely annoying. For many, occasional sneezing, itching and watery eyes is no big deal. Others grow accustomed to the inconvenience and accept it as part of spring or fall, even if their symptoms are more severe.

"It's a quality of life issue," says Ferguson. "It's interesting how impaired people with allergies are. Some are just a little bit, but others have serious effects. I think if you are a productive person, you would want to treat your allergies and be as productive as possible."

"I didn't seek treatment earlier because my allergies had just become a way of life," remembers Crawford. "You just get used to it--I had severe allergies and I didn't even know it. Now I realize how much treatment has improved my quality of life. I should have done it years earlier--it was definitely worth it."

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Keep It Clean

You can reduce your allergic misery if you take steps to keep the culprits out of your house.

For seasonal allergies caused by plants and trees, keep windows shut and the air conditioner on. Purchase an air filter to clean out pollens, molds and dust. Use a dehumidifier in damp areas like the basement. Install wood, tile or vinyl floors rather than carpet because they can be mopped regularly. If you do have carpets, have someone else do the vacuuming or buy a machine designed to reduce dust emissions.

Minimize clutter, book collections, and bric-a-brac, which collect dust and pollens. Keep pets outside or bathe them regularly if they're indoors, and don't let them sleep in your bed. Wash your hair every day to rinse off dust and pollen, and if you've been in the yard, leave shoes at the door and wash your clothes in hot water as soon as possible.

Since many hay fever sufferers are also allergic to dust mites, "The most cost effective thing is to buy a mattress cover," advises Berrilyn Ferguson, M.D. Mattress and pillow covers can provide a barrier between you and the dust mites in your bed, where they live and breed. In addition, treat carpets with an anti-allergen spray that kills dust mites.

You won't be able to eliminate every allergen from your home, but with these steps you can make it a comfortable place even during the peak of allergy season.

Over-the-Counter and Through the Pharmacy

Hay fever strikes some 10 to 30 percent of Americans, and more than half of them turn to over-the-counter medications instead of a doctor's prescription to control their symptoms. Pharmacy aisles are crowded with dozens of individual allergy drugs featuring various combinations of the half dozen active ingredients approved by FDA for allergy relief. Given the variety, consumers may find themselves posing some common questions:

Q: My hay fever strikes every spring and fall. I sneeze, my eyes water, and my throat itches. How do I choose the best medicine for me?

A: For typical hay fever symptoms, three over-the-counter options can help: oral antihistamines, decongestants (both oral and nasal sprays), and a nasal spray containing cromolyn sodium.

Brands such as PediaCare, Robitussin, Comtrex, and Benadryl, as well as generic store brands, contain antihistamines, either chlorpheniramine or diphenhydramine. These drugs are effective for runny noses, sneezing, and itching, but can make you drowsy.

"If the OTC antihistamines are effective in relieving symptoms but are too sedating, a newer less sedating antihistamine can be obtained by prescription," says Linda Hu, M.D., a medical reviewer in FDA's division of OTC drugs. Antihistamines work on a runny nose, but not as well on a stuffy one, so many brands combine an antihistamine with a decongestant (for example, pseudoephedrine). Decongestants can also be found in fast-acting nasal sprays, but these may have a rebound effect and after about three days they'll make your nose even more congested. They are better used for a short-lived cold than an ongoing allergy. One nasal spray that doesn't cause a rebound effect is Nasalcrom (cromolyn sodium). This drug is helpful to prevent your symptoms if started a few days before the allergy season begins and taken continuously. It causes few side effects and will not make you drowsy.

Remember that it's the active ingredient that is important, and many products contain more than one. Read the labels to make sure you're not combining drugs with the same ingredients. Look at the ingredients in the drug product and choose the type of ingredient that will best treat the symptoms you have.

Q: My job requires a lot of driving. Is it safe to take an antihistamine in the morning before I go to work?

A: Probably not. Antihistamines may affect your ability to drive or use machinery even if you don't feel sleepy.

"Drowsiness is the most common side effect of antihistamines and may be a problem for users who need to remain alert," says Hu. "Also, alcohol should be avoided because it may increase the drowsiness caused by antihistamines. If you need to be alert, some prescription antihistamines are less sedating."

Q: I have emphysema and high blood pressure. Can I take an over-the-counter allergy medicine?

A: Antihistamines should not be used by anyone with breathing problems such as emphysema or bronchitis, anyone with glaucoma, by those taking sedatives or tranquilizers, or anyone with difficulty in urination unless directed by their doctors. These drugs dry up secretions and may cause urinary retention and drowsiness, according to Hu.

Antihistamines may also cause dryness of the mouth and eyes and blurred vision.

Decongestants, which are in many OTC allergy medicines, can raise blood pressure. Ask your doctor what, if anything, you can take. Decongestants should not be used by people with heart disease, thyroid disease, or diabetes unless a doctor says it's OK. If you're taking a drug containing an MAO inhibitor (sometimes used to treat depression), never use a decongestant.

Q: I've tried every medicine on the shelves, and I'm still miserable each spring. What else can I do?

A: See your doctor. There may be prescription drugs that are more helpful to you, you may need allergy testing or shots, or your symptoms may be caused by something else entirely.