Allergic Rhinitis (Hay Fever and Rose Fever) and Chronic Nasal Congestion

WHAT IS RHINITIS?

The Nasal Passages and Daily Congestion

The nose is separated into two passages by a wall of cartilage called the septum.

The nasal passages are lined with a membrane that produces mucus. Mucus is one of the body's defense systems:

Rhinitis

If the congestion becomes severe or other changes occur that irritate the nasal passage, rhinitis develops. Rhinitis describes a group of symptoms that include following:

These symptoms may develop as a result of colds or environmental irritants, such as allergens, cigarette smoke, chemicals, changes in temperature, stress, exercise, or other factors.

Infectious Rhinitis. If symptoms last less than six weeks, the condition is referred to as acute rhinitis and is usually caused by a cold or other infection or temporary overexposure to environmental chemicals or pollutants. [Infectious rhinitis is discussed in Colds, Flu, and Bronchitis.]

Chronic Rhinitis . When rhinitis lasts for a longer period, the condition is called chronic rhinitis, and is most often caused by allergies but can also be caused by structural problems or chronic infections. [See Box Causes of Chronic Nonallergic Rhinitis.]

WHAT ARE THE CAUSES AND TRIGGERS OF ALLERGIC RHINITIS?

Biologic Mechanisms and Westernization

The Allergic Response. The body's immune system is designed to produce various factors to fight foreign substances, including bacteria, viruses, and other proteins that the immune system perceives as threatening. An allergic response occurs when the body's immune system over-responds or is hypersensitive to specific non-infectious particles. (Some experts believe that this hypersensitive response originally developed in humans as a way of fighting large invaders, such as parasites and worms.)

The allergic process, called atopy, involves various airborne allergens or other triggers that set off a cascade of events in the immune system leading to inflammation and hyperreactivity in the airways. One description is as follows:

The Role of Early Infections and Westernization. Increasingly, research is reporting that certain infections in early childhood may protect against allergies and even asthma. For example, an important theory blames the dramatic increase in allergies and asthma on the elimination of childhood infections with immunizations, antibiotics, and better hygiene.

The basic theory is as follows:

In support for this theory are studies reporting that being part of a large family or attending day care increases the risk for early infections but reduces the risk of allergies and childhood asthma.

A 2001 Swedish study further found a strong association between allergy development and the absence of certain bacteria carried in the infant's intestines. (Infants who were born in more hygienic environments tended to lack these bacteria.)

It should strongly be pointed out that respiratory and intestinal infections killed thousands of children every year before immunization and good hygiene became widespread. No one recommends stopping vaccinations or reducing cleanliness. Allergic rhinitis is virtually never very serious and asthma, although it can be serious, is rarely fatal in children In addition, in people who are already allergic, certain bacteria can aggravate the allergies.

Having a cold every now and then, however, may be protective. Researchers are also studying the use of certain "good bacteria" called lactobacilli (such as those found in active yogurt cultures) to determine if they may protect against allergies in children, particularly those taking antibiotics.

Overexposure to Indoor Allergens. One study in Germany that tracked East German children after the country became unified reported that children in the areas previously under communism experienced a significant increase in allergies, particularly hay fever, when they were exposed to a Western lifestyle. Included in lifestyle changes were the following:

Some scientists believe that more children are developing allergies because they are spend hours indoors each day engaging in sedentary activities and so are overexposed to indoor allergens. This exposure is intensified by the recent trend of making homes more energy-efficient, which may result in more dust mites being trapped inside.

Triggers of Seasonal Allergic Rhinitis (Hay Fever or Rose Fever)

Seasonal allergic rhinitis occurs only during periods of intense airborne pollen or spores. It is commonly, although inaccurately, called hay fever or rose fever, depending on whether it occurs in the late summer or spring. No fever accompanies this condition, and the allergic response is not dependent on either hay or roses. In general, triggers of seasonal allergy in the US are the following:

It should be noted that major weather changes, such as El Nino, can affect the timing of allergy seasons. For example, in 1998, when the effects of El-Nino were very strong, allergy attacks were markedly increased and maximum tree pollen counts occurred two to four weeks earlier and mold counts two to three months earlier than in 1997.

Triggers of Perennial (Year-Round) Allergic Rhinitis

Allergens in the house can cause year-long allergic rhinitis, called perennial rhinitis. Household allergens may include the following:

Other possible triggers of perennial allergies are being investigated:

WHAT ARE THE SYMPTOMS OF RHINITIS?

The general symptoms of rhinitis are congestion, runny nose, and post-nasal drip, in which mucous drips into the throat from the back of the nasal passage, especially when lying on the back. Symptoms may vary depending on the cause of rhinitis. Symptoms of influenza and sinusitis must also be differentiated from allergies and colds.

Symptom Phases

Symptoms of allergic rhinitis occur in two phases, early and late.

Early Phase Symptoms. The early phase occurs within minutes of exposure to the allergens and includes the following:

Late-Phase Symptoms. The late phase occurs four to eight hours later and may have one or more of the following symptoms:

WHO GETS ALLERGIC RHINITIS?

Allergic rhinitis is the most common chronic condition in childhood and affects between 20 and 40 million Americans of all ages. About 20% of cases are caused solely by seasonal allergies, 40% are due to perennial (chronic) rhinitis, and the rest are mixed. Estimating the number of people with allergic rhinitis is difficult, however. Studies in the US report prevelances as low as 4% to as high as 40%. One reason the studies vary so widely may be due to self-reporting. For example, in response to a Spanish survey, only 9.4% of adolescents said they have hay fever or allergic rhinitis although 30.3% of them describe having symptoms that are characteristic of allergic reactions. It is agreed, in any case, that in the US and around the world the numbers are increasing.

Family History

Genetic factors are the major determinants of allergies.

It should be noted that children with allergic family members are at highest risk for allergies themselves, but they can develop in anyone.

Age of Onset and Duration

Although allergies often appear first in childhood, they may develop at any age. In some cases, allergies go into remission for years and then return later in life. People who develop hay fever in early childhood are likely not to have the allergy in adulthood. Those who develop it after age 20, however, tend to continue to have hay fever at least into middle age.

Allergic Responses in Childhood

Having other allergies increases the risk for allergic rhinitis. Here are some examples:

Birth Month

Some studies report a higher risk of allergies and asthma in children both in winter months and lower risk in those born during the summer.

HOW SERIOUS IS ALLERGIC RHINITIS?

Long-Term Outlook

Although perennial allergic rhinitis is certainly not considered a serious condition, it nonetheless can interfere with many important aspects of life. Seasonal allergic rhinitis tends to diminish as a person ages. The earlier the symptoms start the greater the chances for improvement. In one study over half of allergic subjects reported that by 40 years of age their symptoms had decreased, and 23% were symptom-free.

Fatigue and Sleepiness

People with allergic rhinitis, particularly those with perennial allergic rhinitis, may experience sleep disorders and daytime fatigue. Often they attribute this to medication, but studies suggest congestion may be the culprit in these symptoms. In addition, a 2002 study indicated that patients with seasonal allergies experience hundreds of brief, subtle awakenings, called "microarousals", each night. In such cases, people are not aware that they wake up, but such events can cause fatigue the next day.

Risk for Asthma

Asthma and nonseasonal or seasonal allergic rhinitis often coexist. Evidence suggests that between 20% and 58% of people with allergic rhinitis have asthma. And 70% to 85% of children with asthma have allergies, with the risk being higher from seasonal allergies than perennial allergies. (In one study only 6% of asthma patients had perennial allergies alone, while 24% had seasonal allergies, and 22% had both.)

Some research shows that in young children with allergic rhinitis treating allergies with antihistamines and avoiding allergens may lower the risk for asthma attacks in patients with both conditions and even may help prevent the onset of asthma in children with only allergies.

Increased Risk for Other Allergies

People with allergic rhinitis may be at higher risk for other allergies, including potentially serious food or latex allergies.

Complications of Chronic Rhinitis in Children

Associations with Other Disorders

Chronic Fatigue Syndrome (CFS). Some, although not all, studies have reported that a majority of CFS patients have allergies to foods, pollen, metals (such as nickel or mercury), or other substances. One theory is that allergens, like viral infections, may trigger a cascade of immune abnormalities leading to CFS. (Most allergic people, in any case, do not have CFS.) Some research indicates that people with both allergies and emotional disorders, such as anxiety or depression, may be more vulnerable to the effects of the inflammatory response, a harmful overreaction of the immune system that can cause fatigue, joint aches, and fever as well as hormone and brain chemical disturbances.

One theory that may help tie in some of the various factors common to CFS suggests that allergies, stress, and infections may deplete a chemical in the body called adenosine triphosphate (ATP). This chemical stores energy in cells, and studies have reported a deficiency in many CFS patients. Supporting this theory was a study in which patients reported reduced CFS symptoms after they took a vitamin-like supplement called NADH, which increases ATP levels.

Rheumatoid Arthritis. Reports from a Dutch study suggest that hay fever sufferers have a reduced risk of developing rheumatoid arthritis, and, conversely, arthritis patients are less likely to have hay fever. Experts suggest that the immune response in one disorder may tend to neutralize the other.

WHAT TESTS MAY BE REQUIRED TO DIAGNOSE RHINITIS?

Medical and Personal History

To determine the cause of rhinitis, the physician will ask a number of questions. They may include the following:

Physical Examination

The physician will usually examine the inside of the nose with an instrument called a speculum. This is a painless examination and allows the doctor to check for redness and other signs of inflammation. The doctor will also usually check the eyes, ears, and chest.

Allergy Skin Tests

A skin test is a simple method for detecting common allergens. Patients usually are tested for a panel of common allergens. Skin tests are rarely needed to diagnose mild seasonal allergic rhinitis, since the cause is usually obvious. The test is not appropriate for children less than three years old.

The procedure is as follows:

The test is not completely accurate. For instance, a 2001 study reported that testing detected allergies in less than half of children with rhinitis. Furthermore, about 15% to 20% of people may have a skin reaction without actually having an allergy.

Laboratory Tests

Nasal Smear. The physician may take a nasal smear. The nasal secretion is examined microscopically for factors that might indicate a cause, such as increased numbers of white blood cells, indicating infection, or high counts of eosinophils. (High eosinophil counts indicate an allergic condition, but low counts do not rule out allergic rhinitis.)

Tests for IgE. Blood tests for IgE immunoglobulin production may also be performed. One called the radioallergosorbent Test (RAST) is used to detect increased levels of allergen-specific IgE in response to particular allergens. Blood tests for IgE may be less accurate than skin tests. They should only be performed on patients who cannot undergo skin testing or when skin test results are uncertain.

Imaging Tests

In people with chronic rhinitis, the physician may also check for sinusitis. Imaging tests may be useful if other tests are ambiguous.

Nasal Endoscopy

In certain cases of chronic or unresponsive seasonal rhinitis, a physician may use endoscopy to examine for any irregularities in the nose structure. Endoscopy employs a tube inserted through the nose that contains instruments and a miniature camera to view the passageways.

WHAT ARE THE GENERAL GUIDELINES FOR TREATING ALLERGIC RHINITIS?

If rhinitis is caused by non-allergic conditions, particularly if there are accompanying symptoms indicating a serious problem, the physician should treat any underlying disorders. If rhinitis is caused by medications, the patient should consider any possible alternatives, if appropriate.

Preventing the Onset of Allergy Attacks

Patients with chronic allergic rhinitis may require daily medications. Patients with severe seasonal allergies may be advised to start medications a few weeks before the pollen season, and to continue it until the season is over. Effective medications include the following:

All drug treatments have side effects, some very unpleasant and, in rare cases, serious. Patients may need to try different drugs until they find one that relieves symptoms without producing excessively distressing side effects. [For specific information on all of these agents see individual sections below.]

Treating Nasal Symptoms of Allergic Rhinitis

Mild allergy attacks usually require little more than reducing exposure to allergens and using a nasal wash. Dozens of drugs are available for treating allergic rhinitis. Many are available over the counter but some require a prescription. They include the following:

[For specific information on these agents see individual sections below.]

Special Considerations for Children with Allergies. Because seasonal allergies generally last only a few weeks, most physicians do not recommend the more potent prescription treatments for children. It is important for parents to determine if the child is actually under severe distress and that the parent is not simply responding to their own anxiety when they hear the child snorting or snoring. Prescription drugs are required only in some severe cases. Of note, however, in children with both asthma and allergies, intense treatments for allergic rhinitis may also improve asthmatic symptoms.

Treating Itchy Eyes.

The following are eye drops for itchy eyes. Others are also available. Customers respond differently to these products, and report a wide range of effectiveness.

General Side Effects and Warning.

People who have heart disease, high blood pressure, an enlarged prostate gland, and glaucoma should avoid eye drops.

WHAT ARE NATURAL OR ALTERNATIVE AGENTS FOR ALLERGIC RHINITIS?

Nasal Wash

For mild allergic rhinitis, a nasal wash can be helpful for removing mucus from the nose. A saline solution can be purchased at a drug store or made at home. One study reported that neither a homemade solution (using one teaspoon of salt and one pinch of baking soda in a pint of warm water) nor a commercial hypertonic saline nasal wash had any effect on symptoms. Further, one preliminary study found that over-the-counter saline nasal sprays that contain benzalkonium chloride as a preservative may actually worsen symptoms and infection.

Some physicians, however, advocate a traditional nasal wash that has been used for centuries and is different from that used in the study. It contains no baking soda and uses more fluid for each dose and less salt. The nasal wash should be performed several times a day.

Simple method for administering a nasal wash is the following:

The solution may also be inserted into the nose using a large rubber ear syringe, available at a pharmacy. In this case the process is the following:

Natural Remedies

In one study, nearly half of asthma or allergy sufferers resorted to alternative treatments. To date, however, evidence does not support any value from most alternative therapies, including high-dose vitamins, urine injections, homeopathic remedies, and most herbal remedies. Some relaxation methods, such as massage therapy, may be beneficial in reducing stress related to allergy symptoms. The following are examples of two recent promising areas of research:

HOW ARE DECONGESTANTS USED TO PREVENT ALLERGY SYMPTOMS?

For mild allergic rhinitis, a nasal wash can be helpful for removing mucus from the nose. Decongestants may help dry nasal congestion. They work by shrinking vessels in the nose. By reducing blockage, they decrease the risk of developing sinusitis caused by viruses or bacteria. Many over-the-counter decongestants are available, either in tablet form or as nasal or inhaled decongestants that are applied directly into the airways as sprays, drops, or vapors.

Nasal-Delivery Decongestants

Nasal-delivery decongestants are applied directly into the nasal passages with a spray, gel, drops, or vapors. Nasal forms work faster than oral decongestants and have fewer side effects. They often require frequent administration, although long-acting forms are now available. Ingredients and brands of nasal decongestants include the following:

Long Acting Nasal-Delivery Decongestants. They are effective in a few minutes and remain so for six to 12 hours. The primary ingredient in long-acting decongestant is the following:

Short-Acting Nasal-Delivery Decongestants. The effects usually last about four hours. The primary ingredients in short-acing decongestants are the following:

Dependency and Rebound. The major hazard with nasal-delivery decongestants, particularly long-acting forms is a cycle of dependency and rebound effects. The 12-hour brands pose a particular risk for this effect. This effect works in the following way:

Tips for Use. The following precautions are important for people taking nasal decongestants:

Oral Decongestants

Oral decongestants also come in many brands, which mainly differ in their ingredients. The most common active ingredient is pseudoephedrine (Sudafed, Actifed, Drixoral). The alternative decongestant, phenylpropanolamine (PPA) was taken off the market. [ See Warning Box,Decongestants and Phenylpropanolamine.]

Side Effects of Decongestants

Decongestants have certain adverse effects, which are more apt to occur in oral than nasal decongestants and include the following:

Individuals at Risk for Complications from Decongestants. People who may be at higher risk for complications are those with certain medical conditions, including disorders that make blood vessels highly susceptible to contraction. Such condition include the following:

Anyone with these conditions should not use either oral or nasal decongestants without a doctor's guidance. Other groups who should also use these agents with caution are the following:

HOW ARE ANTIHISTAMINES USED IN ALLERGIC RHINITIS?

Histamine is one of the chemicals released when antibodies overreact to allergens and is the cause of many symptoms of allergic rhinitis. Anti histamines have the following benefits:

Experts recommend that patients take them before an anticipated allergy attack if possible.

Many antihistamines are available and include short-acting and long-acting forms. They are available in tablet, nasal-inhaler, eye drop, and syrup form. Antihistamines are generally categorized as first- and second-generation, which generally are based on whether they have ingredients that cause greater or lesser sedation.

There are some notes of caution when taking any generation antihistamine:

First- Generation Antihistamines

First-Generation Antihistamines Ingredients and Brand Names. The older, so-called first generation antihistamines include:

First-generation antihistamines contain compounds called anticholinergics, which tend to produce the side effects that differentiate this group from second-generation antihistamines.

Side Effects. Side effects include the following.

Tips for Using First-Generation Antihistamines. To offset the sedative effect, the following tips may be helpful:

It should be noted that sedation lessens over time.

Second-Generation Antihistamines

Second-Generation Antihistamines Ingredients and Brand Names. The newer second-generation antihistamines do not contain anticholinergics and so do not usually cause drowsiness at recommended doses as the first generation antihistamines do. The second-generation agents include the following:

At the time of this report the FDA has ruled that Allegra, Claritin, and Zyrtec are safe for over-the-counter use, but the manufacturers have not yet applied for this status. (Claritin is likely to be the first to be available, in which case it is likely be sold for treating hives.) Women who are pregnant or nursing should avoid these medications unless recommended by a physician.

One 2001 comparison study suggested that Claritin was more effective than Allegra in improving symptoms in a shorter period of time. Studies further suggest that cetririzine (Zyrtec) is more effective than either of these agents in improving symptoms, including in children, although cetririzine causes more drowsiness at higher doses.

Most appear to be safe in children, although only cetirizine and loratadine are approved for those under five years of age. Studies with cetirizine have reported fewer symptoms in children allergic to dust mites, and a 2002 study reported that infants with allergies who were given cetirizine were much less likely to develop asthma later on than untreated infants. Loratidine (Claritin) at this time is generally the preferred agent for younger people, however, because it has the least negative effect on concentration and learning. It is also available in liquid doses.

Side Effects and Precautions.

Drug and Food Interactions. Two earlier second generation drugs, terfenadine (Seldane) and astemizole (Hismanal), in rare cases, caused dangerous heart rhythm abnormalities, particularly in high doses or in people who have liver disease or are taking certain other medications or ingesting grapefruit juice. Both Seldane and Hismanal have been taken off the market. Allegra, Zyrtec, and Claritin do not appear to pose any of the dangers associated with Seldane.

Until more is known, anyone who takes a second-generation antihistamine, though, should probably avoid or use with caution combinations with grapefruit juice or the drugs that caused problems with Seldane and Hismanal. Such medications include the following:

Nasal-Spray Antihistamines

Azelastine (Astelin) and levocabastine (Livostin) are available in nasal spray form. They can reduce nasal congestion as well as allergy symptoms. Both reduce symptoms, although azelastine may be more effective in some patients. Their disadvantages are a bitter taste, drowsiness, and expense.

Combination Antihistamines and Decongestants

Many prescription and non-prescription products that combine antihistamines and decongestants are available. A small sample of these combinations sold over the counter includes Allerest, Sudafed Severe Cold Formula, Vicks DayQuil, Benadryl Allergy/Sinus, Contac Day/Night Allergy & Sinus. Prescription combinations include Claritin-D, Allegra D, and Zyrtec-D. They may be effective for all symptoms within 60 minutes, with congestion clearing up first. As a rule, children should not be given combination remedies, which can cause headaches, agitation, and loss of appetite.

HOW ARE CORTICOSTEROIDS AND OTHER ANTI-FLAMMATORY DRUGS USED FOR ALLERGIC RHINITIS?

A number of agents are available for reducing the inflammatory response in allergies and so preventing an attack in the first place.

Corticosteroid Nasal Sprays

Benefits of Corticosteroid Nasal Sprays. The most important anti-inflammatory agents are corticosteroids, also called glucocorticoids or, most commonly, steroids. Corticosteroids do not relieve symptoms immediately but may take several hours before their effects are felt. Nasal spray steroids are proving to be safe and have the following benefits:

Comparison studies are reporting that nasal steroid sprays are more effective than the second generation antihistamines loratadine (Claritin) and cetririzine (Zyrtec). One study also indicated that nasal steroid treatment was more effective than immunotherapy (allergy shots).

Nasal-Spray Brands. Corticosteroids available in nasal spray form include the following:

Some experts recommend beclomethasone, triamcinolone, budesonide or flunisolide for short-term therapy (one to two months) and mometasone furoate or fluticasone for longer-term treatment.

Side Effects. Corticosteroids are powerful anti-inflammatory drugs. Although oral steroids can have many side effects, the nasal-spray form affects only local areas, and the risk for wide spread side effects is very low unless the drug is used excessively.

Cromolyn

Cromolyn serves as both an anti-inflammatory drug and a specific blocking agent for allergens. The standard cromolyn nasal spray (Nasalcrom) is not as effective as steroid nasal sprays but is effective for many people with mild allergies. It is one of the preferred first-line therapies for pregnant women with mild allergic rhinitis. It may take up to three weeks for a person to experience full benefit.

Side Effects. Cromolyn has no major side effects, but minor ones include nasal congestion, coughing, sneezing, wheezing, nausea, nosebleeds, and dry throat. The spray can cause burning or irritation.

Leukotriene-Antagonists

Leukotriene-antagonists are oral drugs that block leukotrienes, powerful immune system factors that are important in causing airway constriction and mucus production in allergy-related asthma The leukotriene-antagonists include zafirlukast (Accolate), montelukast (Singulair), zileuton (Ziflo), and pranlukast (Ultair, Onon). They are currently being used for asthma. Evidence is now strongly suggesting that they have an important role in allergic rhinitis, although they do not appear to be as effective as steroid nasal sprays. For example, several studies have reported that montelukast (Singulaire) substantially reduces hay fever symptoms in children. A 2000 study has also found that zafirlukast (Accolate) helps relieve nasal symptoms from cat allergies.

HOW IS IMMUNOTHERAPY USED FOR ALLERGIC RHINITIS?

Immunotherapy (commonly referred to as "allergy shots") is a highly effective treatment for patients with allergies. It is based on the premise that people who receive injections of a specific allergen will lose sensitivity to it. The most common allergens for which shots are given are house dust, cat dander, grass pollen, and mold.

Immunotherapy has many advantages:

Candidates

Candidates for Immunotherapy. Immunotherapy (allergy shots) may be given to anyone over seven whose allergies are severe and do not respond to medication. At an international 2000 conference, many experts agreed that immunotherapy should be considered as soon as possible for children with asthma and allergies. Immunotherapy is safe for pregnant women who are already receiving it, although half-strength doses are generally recommended and it should not be started during pregnancy.

Individuals at Risk for Complications. People who should probably avoid immunotherapy include the following:

Administering Therapy

The major downside to immunotherapy is that it requires a prolonged course of weekly injections ("allergy shots"). The process generally follows this course:

After stopping immunotherapy, about one third of allergy sufferers no longer have any symptoms, one third have improved symptoms, and one third relapse completely.

The use of an injection series is effective but patients often fail to comply with the regimens. Some other schedules and delivery methods are being investigated that might make the program easier and less distressing.

Rush Immunotherapy. Investigators are studying so-called rush immunotherapy, in which patients achieve the full maintenance dose with several shots a day over a period of three to five days. Rush therapy uses modifications that reduce the risk of severe reactions to excessive doses. Studies are suggesting that it is effective and safe, with few side effects other than itching. Patients must be monitored closely during this period, however, for severe reactions.

Oral Forms. Trials are underway to test oral forms of immunotherapy. One method uses an oral gelcap and another uses a sublingual (under-the-tongue) tablet. (Previously, oral forms have not been feasible because digestive enzymes in the intestine rendered the therapy useless.) Small studies are promising, but larger ones are needed to determine the safety and effectiveness of this approach.

Side Effects and Complications of Immunotherapy

Injections for ragweed and, possibly, excessive doses of dust mites, have higher risks for side effects than other allergy shots. If complications or allergic reactions develop, they usually occur within 20 minutes although some can develop up to two hours after the shot is given.

Side effects of immunotherapy include the following:

It should be noted that in one 10-year study, the incidence of any adverse effect was less than two-tenths of one percent, and the great majority of events were mild. The risk for a fatal response is estimated to be one per 63 million injections. (As a comparison, the risk for a fatal reaction to penicillin is much higher, one per 7.5 million injections.)

Investigative Immunotherapy Approaches

Vaccines. Of particular interest is the development of immunotherapeutic vaccines that use more specific targets to produce an insensitivity to allergens. One such vaccine uses a small protein from the allergen, which is injected into the patient. Other vaccines under investigation are those that use the allergen's genetic material (its DNA) to promote tolerance to the allergen.

Monoclonal Antibodies. Monoclonal antibodies (MAb) are genetically-developed antibodies that are designed to target and attack very specific factors. A MAb known as omalizumab (Xolair) prevents the antibody immunoglobulin E (IgE) from triggering the inflammatory events that lead to allergies and also to asthma. Studies are very promising for its use in treating seasonal allergies as well.

WHAT LIFESTYLE MEASURES ARE USED TO PREVENT ALLERGIC RHINITIS?

General Guidelines

Important irritants or allergens that should be avoided include the following:

Indoor Protection Against Allergens

Some experts believe that reducing the risk factors for asthma in the home could reduce asthma in children by 40%.

Controlling Pets. People with asthma who already have pets and are not allergic to them probably have a low risk for developing such allergies later on. In fact, early intense exposure to pets in small children may help protect them against allergies and asthma.

In children who have an existing allergy to pets, however, the pets should be given away or kept outside. If this isn't possible, they should at least be confined to carpet-free areas outside the bedroom. Cats harbor significant allergens, which can even be carried on clothing; dogs usually present fewer problems. Washing animals once a week can reduce allergens. Dry shampoos, such as Allerpet, are now available for both cats and dogs that remove allergens from skin and fur and are easier to administer than wet shampoos.

For small children, stuffed animals might serve as a comforting replacement, although they might harbor dust mites. Putting stuffed animals in the freezer for 24 hours before washing them kills the dust mites. For best effect, this process should be done weekly.

Preventing Exposure to Cigarette Smoke. Parents who smoke are strongly urged to make strenuous efforts to quit. [For help in quitting, see smoking.]

Controlling for Dust. House dust is a reservoir for pollen, so keeping a house dust-free is helpful. A 2002 study reported that spray furniture polishing is very effective for reducing both dust and allergens.

Air cleaners, filters for air conditioners, and vacuum cleaners with HEPA filters can help remove particles and small allergens found indoors. Neither vacuuming nor the use of anti-mite carpet shampoo, however, is effective in removing mites. In fact, vacuuming stirs up both mites and cat allergens. Carpets and rugs are major sources of allergens in any case and should be avoided if possible.

Bedding and Curtains. Using semipermeable coverings to fully encase mattresses and pillows is the most proven effective step in reducing dust mite levels. (Vinyl mattress covers limit airflow and may also exacerbate, or even cause, asthma in children. Synthetic pillows may pose a significantly higher risk for severe asthma attacks in children than feather or no pillows.) Curtains should be replaced with shades or blinds and bedding washed using the highest temperature setting.

One 1999 study found that children sleeping in bottom bunk beds are significantly more likely to develop asthma than siblings occupying the upper bunks. Families with asthmatic or allergic children should avoid bunk beds or be sure that children with asthma sleep in the top bunk. Even with standard beds, it may be useful to have them sleep as high off the floor as possible.

Reducing Humidity in the House. Dust mites thrive in humidity and damp houses increase the risk for mold. If humidifiers are being used, humidity levels should not exceed 40% and they should be cleaned daily with a vinegar solution.

Exterminating Cockroaches and House Mice. Cockroaches should be eliminated by professional exterminators, although a study reported that ridding a home of cockroaches and cleaning the house using standard housecleaning techniques failed to eliminate the cockroach allergens themselves. Mice should be eliminated, and attempts should be made to remove all dust, which might contain mouse urine and dander.

Reducing indoor humidity can lower dust mite populations. On-going humidifiers, then, can be counterproductive because dust mites thrive in humidity, and because they can develop mold if not cleaned daily with a vinegar solution; humidity levels should not exceed 40%. Patients with asthma should choose electric ovens rather than gas, which release nitrogen dioxide, a substance that can aggravate asthma symptoms.

Outdoor Protection

Avoiding Outdoor Allergens. The following are some recommendations for avoiding allergens outside:

WHERE ELSE CAN PEOPLE WITH RHINITIS GET HELP?

American College of Allergy, Asthma & Immunology, 85 West Algonquin Road, Suite 550, Arlington Heights, IL 60005. Call (847-427-1200) or fax (847-427-1294) or ( http://www.acaai.org )

This organization publishes information sheets on specific allergies and offers a number for referrals to allergists in local areas. Their web site is excellent.

National Jewish Center for Immunology and Respiratory Medicine, 1400 Jackson Street, Denver, CO 80206. Call (800-222-LUNG or 303-355-LUNG) or for the recorded service Lung Facts call (800-552-LUNG) or ( http://www.njc.org/ ).

National Allergy Bureau and American Academy of Allergy, Asthma, and Immunology, 611 East Wells Street, Milwaukee, WI 53202. Call (800-822-2762) or ( http://www.aaaai.org/ ). This organization hasa hotline for getting the weekly pollen and mold-spore count.

The American Lung Association, 1740 Broadway, New York, New York 10019-4374. Call (800-LUNG-USA) or ( www.lungusa.org )

Allergy Control Products, Inc., 96 Danbury Road, Ridgefield, CT 06877.
Call (800-422-DUST or 3878) or on the Internet ( http://www.allergycontrol.com )
Sells products for people with allergies and asthma.

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. Copyright 2002 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.

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