It’s Spring Again and Allergies Are In Full Bloom

May 10 00:00 2001 Print This Article

Chances are that you would just as soon not think about your nose. As long as it lets air in and out fairly easily, sniffs a nice aroma now and then, and keeps eyeglasses in place, a nose is, well, forgettable.

But for 25 million to 30 million Americans who suffer from seasonal allergic rhinitis--better (if inaccurately) known as hay fever--it is sometimes hard to think of anything but their noses. When a hay fever victim's particular nemesis is in the air, he or she is apt to be preoccupied by a constant struggle against the ailment's classic symptoms--watery nasal discharge, runny eyes, violent fits of sneezing, and itching that can affect not just the nose, but the roof of the mouth and even the Eustachian tubes connecting the inner ear to the back of the throat.

If tree pollen is the culprit, this all-out barrage against the nose and its neighbors usually strikes in early spring. Grass pollen tends to be troublesome in late spring and summer, and the deservedly notorious ragweed pollen is most abundant in the fall. Depending on where they live, hay fever victims who react to all three types of pollen may get a respite only in mid-summer and the dead of winter.

On the other hand, a hay fever sufferer who is allergic to molds, house dust, or animals may have to contend with symptoms the year 'round. So do people whose attacks are triggered by industrial pollutants, cigarette smoke, and other airborne irritants and allergens where they live or work. These unfortunate souls have "perennial allergic rhinitis." Their hay fever never lets up.

If that is the bad news, the good news is that a lot can be done to help hay fever sufferers cope with the disease. Better understanding of the complex events involved in an allergic reaction has made possible substantial improvement in the care of allergy patients, whether they have hay fever, asthma, food allergies, or any of a wide range of distressing and sometimes life-threatening allergic diseases. Medical science cannot cure allergies the way it can pneumonia. But advances in treatment and prevention allow millions of people to avoid the torment that can plague anyone unfortunate enough to "have allergies."

ALLERGIES OR A COLD?

Allergists (physicians who specialize in treating allergies) think that a good deal of allergic disease is unrecognized and therefore untreated. One reason is that seasonal allergies can easily be mistaken for a cold. Careful observation and common sense are useful guides to whether a stuffy, runny nose and sneezing signal a cold or an allergy. If the symptoms last more than a week or so, if they go on virtually all of the time, if they start and stop at the same time every year, flare up around cats or horses (principal causes of animal allergy), or otherwise follow a consistent pattern, allergy ought to be suspected. To be more certain, however, appropriate tests should be done by a physician, preferably an allergist.

The diagnosis of allergic rhinitis--the medical term for the inflamed, runny nose that's the main symptom of "allergies"--is based on a detailed patient history and examination of the nose. But the most critical step is skin testing. Tiny, diluted amounts of suspected allergens are injected under the skin or applied to a small scratch or puncture on the patient's arm or back. Within about 15 minutes, if the patient has IgE antibodies (see accompanying article) to an allergen being tested, a small raised area surrounded by redness--the "wheal and flare" reaction--will appear at the test site. The size of the skin reaction indicates how sensitive the patient is to the allergen that caused it.

Paul C. Turkeltaub, M.D., of FDA's Center for Biologics Evaluation and Research, and researchers at the National Center for Health Statistics examined information on allergen skin testing collected between 1976 and 1980 in the Second National Health and Nutrition Examination Survey. Among more than 16,000 people aged 6 to 74, about one in five had skin reactions to at least one allergen. Ryegrass and ragweed pollen each produced reactions in over 10 percent of the people tested, 6.2 percent were sensitive to house dust, and 2.3 percent showed a reaction to cats. More than twice as many people reacted to allergens found outdoors than to those found indoors.

Not everyone who tests positive for specific IgE antibodies necessarily has allergy symptoms. Nevertheless, many allergists think that allergic disease of one kind or another--hay fever, asthma, drug allergy, or an allergic reaction to certain foods or insect stings--is likely to appear sooner or later in a person who has no symptoms but who has a positive skin test. About 80 percent of people who develop allergic rhinitis do so before the age of 30. But the disease has also first appeared in people in their 70s or 80s.

SHOTS AND OTHER RELIEF

Before the 1940s brought the general availability of antihistamines, hay fever sufferers could get little help from the pharmacy. A hundred and fifty years ago, the English clergyman, wit, and hay fever victim Sydney Smith--he said his sneezes could be heard for six miles--put opium in his nostrils to relieve "this little upstart disease." Today allergic rhinitis can be controlled by more effective and much less dangerous drugs.

Antihistamines, available both over the counter and by prescription, remain the most widely used agents to treat hay fever symptoms. They can be highly effective in controlling itching and sneezing, but do less well in clearing nasal congestion. Antihistamines are most effective when used regularly rather than sporadically. Their chief undesirable side effects are drowsiness and excessive drying of tissues. Newer antihistamines, such as the prescription medication Seldane (terfenadine), are less apt to cause these side effects.

Nonprescription decongestants that shrink blood vessels in and around the nasal passages may help relieve nasal stuffiness. Decongestants are often sold in combination with antihistamines in the form of tablets, capsules, caplets and liquids. Others are sold as nose drops or sprays. While very effective for short-term use--a few days at most--overuse of nose drops and sprays can cause a "rebound" effect in which the congestion comes roaring back worse than ever. Patients can get caught in a vicious circle of use, relapse, and more use. The only solution is to stop using the drug altogether.

Intal or Nasalcrom inhalers (active ingredient cromolyn sodium), available by prescription, were first used against asthma and are proving useful in treating hay fever as well. For most people, inhaled cromolyn has few if any side effects, but must be taken frequently--every four hours--to be of maximum benefit. The corticosteroids, hormone-like drugs that suppress the immune response, may also be useful in relieving allergy symptoms. They are usually administered as sprays, but are sometimes taken by mouth. While long-term use of oral corticosteroids can depress the activity of the adrenal glands, resulting in diminished resistance to infection, and cause other serious side effects, the nasal preparations used to treat allergic rhinitis are not thought to have any effect on the body as a whole. Corticosteroids are available only by prescription.

Allergen immunotherapy--"allergy shots"--offers another effective approach to controlling hay fever symptoms. First employed in the 1920s, immunotherapy consists of injecting gradually larger amounts of the allergens that cause the patient's allergic response. At the beginning of the treatment the dose is intentionally much too small to cause a reaction. The dose is gradually increased to a level that protects the patient from whatever is causing the allergy. It usually takes six to 12 months to reach a protective dose. Once protection has been achieved, patients are given maintenance shots at four- to six-week intervals to keep symptoms under control. Whether or not the patients can successfully stop receiving allergy shots is uncertain. Studies suggest that protection fades if the shots are discontinued. For that reason, some allergy specialists recommend that they be continued indefinitely.

AIMING FOR IMPROVEMENTS

FDA is actively seeking to standardize the commercially available extracts used in skin testing and immunotherapy to improve their safety and effectiveness. The agency has two main objectives: expanding the availability of single-allergen extracts (individual kinds of pollen, for example, rather than extracts containing mixtures of several allergenic pollens); and standardizing extracts on the basis of how strong a skin reaction they produce. Studies have shown, for example, that weed and grass pollen extracts are more than 10,000 times as potent in producing skin reactions as extracts made from white pine and mountain cedar pollen. The labeling of standardized extracts reflects such differences in terms of "allergy units." Using single-allergen, standardized extracts, physicians are better able to tell precisely what causes a patient's symptoms and to plan, if necessary, the most effective course of allergy shots.

Immunotherapy has proven effective in hay fever sufferers and can be little short of miraculous for some patients who cannot get adequate relief either from avoiding allergens or from medication. Allergy shots are, however, time-consuming and costly and entail a slight risk of causing the kind of reaction they are meant to prevent. Because such a reaction can be serious, doctors like to monitor patients for at least 20 minutes after giving the shot.

The best course of action in treating hay fever is to get a careful diagnosis and discuss treatment options with an allergist. Once a hay fever sufferer's problem has been diagnosed, a doctor often can show how symptoms can be controlled by avoidance of the allergen or allergens involved or by the careful use of over-the-counter antihistamines and decongestants. If prescription drugs or immunotherapy are called for, a physician can recommend the most appropriate course of treatment. The important thing is that virtually every hay fever sufferer can be helped by prevention and treatment.

Noses are remarkable. They filter the air we breathe, warm it when it's too cold, and moisten it when it's too dry. They alert us when food might be unsafe to eat, and some noses can even smell a rain storm coming. Yet, with the possible exception of Bob Hope, we would all be grateful if noses went about their impressive variety of tasks unnoticed. For hay fever victims, that would be a blessing. Thanks to medical science, it's a blessing millions of them can enjoy. Ken Flieger is a free-lance writer in Washington, D.C.

AN OVERACHIEVER IMMUNE SYSTEM

Seasonal allergic rhinitis--hay fever--is the most common allergic disease. Its medical name means inflammation of the membrane lining the nose caused by exposure to an allergen at specific times of the year. (Hay is almost never its cause, and fever is not one of its symptoms, but the misnomer has stuck since it was coined more than 160 years ago.) Research, most of it in the 20th century, has demonstrated that allergy is actually an altered or exaggerated immune response. In an allergy-prone person the immune system reacts powerfully to foreign substances, such as pollen, that simply do not bother most of us.

The phenomenon of immunity has long been recognized. Ancient scribes reported that survivors of plague seemed to be protected if the disease struck again. Fifteenth century Chinese and Arab physicians tried injecting people with pus taken from smallpox victims. Sometimes the result was a mild case of smallpox that protected against the more serious form of the disease. Sometimes, too, the outcome was severe smallpox and death.

Two centuries ago, an English physician named Edward Jenner successfully immunized a young boy against smallpox by injecting him with a fluid from a cowpox sore--hence the term vaccination--from vacca, Latin for cow. But it was not until the late 19th and early 20th centuries that scientists began to explore the immune system and discover that it is responsible for a number of illnesses, including allergies.

The mechanisms by which the human body recognizes its own components and distinguishes them from foreign substances are among the most elegant products of evolution. (See "The Immune System: Your Body's Department of Defense," FDA Consumer, March 1988.) Although they do not understand it fully, scientists believe the immune system consists of two main branches. One works through the action of white blood cells called T lymphocytes, or simply T cells. T cells attack foreign materials directly and also produce substances that summon other parts of the immune system to help destroy an invader. A deficit of T cell-mediated immunity is characteristic of acquired immune deficiency syndrome.

The other branch of the immune system is the one we associate with antibodies--highly specialized proteins manufactured by B lymphocytes--and antigens--enzymes, toxins, or other foreign substances that provoke a response from the body. When B cells encounter antigens, such as those on the surface of bacteria, they multiply and produce antibodies that destroy the invading germ or make it vulnerable to attack by other parts of the immune system. Once B cells have learned to make an antibody against a specific antigen, they go on making it indefinitely. This is why vaccines can induce permanent immunity against some diseases.

Ironically, it is the immune system's ability to maintain constant readiness against a repeat onslaught by an antigen that makes millions of people susceptible to allergic disease. For reasons that are not entirely clear, some antigens cause B cells to make a kind of antibody called immunoglobulin E--IgE for short. (Antigens that provoke IgE formation are referred to as allergens because they can cause an allergic reaction.) The first time an allergy-prone person is exposed to an allergen--pollen or house dust for example--the B cells respond by making IgE antibodies tailored to counteract the allergen. These IgE antibodies attach themselves to mast cells that are abundant in the respiratory tract, digestive system, and skin and to basophils, cells circulating in the blood.

The next time an allergen and its IgE antibodies come together, mast cells and basophils release powerful substances called mediators, among them histamine, that cause the allergic reaction. These mediators are fairly rapidly neutralized by the body. But as long as the allergen is present, histamine and other mediators will continue to be released from mast cells and basophils, and the patient's allergy symptoms will persist.

No one knows for sure why some people have allergies while most do not. Genetics appears to play a part; people who suffer from allergies usually have a close relative with similar problems. Susceptibility seems to be related to a person's capacity to produce IgE antibodies. Yet only 30 percent to 40 percent of people with allergic rhinitis have high IgE levels, and individuals with low IgE levels can still suffer from hay fever and other allergies.

In view of all the grief they cause, you have to wonder if IgE antibodies are good for anything. The answer may well be yes. Studies suggest that several kinds of human parasites provoke the formation of IgE antibodies and are rapidly destroyed by them. (These amoebas and worms are no longer common in this country, but they still cause serious health problems in underdeveloped parts of the world.) Looking at this intriguing discovery, a Swedish immunologist has speculated that "pollen allergy might partly be an undesirable consequence" of modern society's success in ridding itself of parasites and the diseases they cause.

ABSENCE MAKES THE NOSE GROW FONDER

Once hay fever has been diagnosed and the responsible allergen or allergens identified, the first line of defense is prevention--avoiding the pollen, house dust, mold spores, scales shed by the skins of animals (dander), or other substances that provoke an allergic reaction.

Sometimes this can be fairly easy. A patient may hate to part with a pet cat or give up horseback riding, but that may be all it takes to be free of symptoms. People allergic to mold spores may solve their problem by keeping out of damp, musty areas. They may also be well advised to avoid foods such as peanuts that may contain mold spores and not to take penicillin and similar drugs that can cause an allergic reaction in mold-sensitive people.

If house dust is the problem, frequent and thorough cleaning of the floors, fabrics such as carpets and curtains, upholstered furniture, and bedding can be beneficial. So can the use of high-efficiency indoor air-filtering devices (not those built into ordinary heating and air conditioning systems) that trap dust particles. (Filtering devices that really help don't come cheap. Beware of inexpensive--and ineffective--substitutes.) Persuasive evidence points to microscopic mites as the prime offenders in house dust allergies. While these spider-like creatures thrive during warm summer months, they may actually be more troublesome in colder weather when fragments of dead mites are more readily dispersed in the air and inhaled.

It is more difficult to avoid pollen and other outdoor airborne allergens. Air conditioning helps in homes, automobiles and workplaces. Simply keeping doors and windows closed can lower the allergen content of indoor air. Hay fever symptoms can be brought on by pollen concentrations as low as 20 grains per cubic meter of air; so during certain seasons, no outdoor area can be assumed pollen-free. Yet it is wise to be especially wary of areas known to have high concentrations of allergens. Another prudent measure for allergic rhinitis sufferers is to avoid irritants such as tobacco smoke, fumes, polluted air, and hair sprays.

It is seldom helpful to move someplace else to escape hay fever-causing pollen. Every part of the country has varieties of trees, weeds and grasses that shed allergenic pollen. People who try moving to the West Coast to escape ragweed pollen (ragweed does not grow in California, Oregon or Washington) may discover that they are allergic to a pollen found in the new location. Furthermore, pollen grains have been found in air samples collected as far as 400 miles at sea. The adage "you can run but you can't hide" is all too true for most hay fever sufferers.


Source: FDA Consumer Magazine; reprinted with permission from the FDA

Related Links

write a comment

0 Comments

No Comments Yet!

You can be the one to start a conversation.

Add a Comment

Your data will be safe! Your e-mail address will not be published. Also other data will not be shared with third person.
All fields are required.