Types Of Asthma

It is convenient to divide asthma into several subtypes. These subtypes may be somewhat artificial, since most asthmatics share several features of each subtype, but these distinctions help to better understand and treat asthma. Asthma is generally divided into "idiosyncratic" and "stimuli evoked."

 

"Idiosyncratic" means we don't know what caused the attack. True idiosyncratic asthma is rare, so what this name usually implies is that we haven't discovered what provoked the attack. "Stimuli evoked" means that the asthma attack was caused by exposure to a particular stimulus. The substances that can cause an attack are almost endless, ranging from pollen to cold air. It is convenient to divide stimuli-evoked asthma into different categories: allergic, infectious, emotional, drug- or food-related, environmental, occupational or work-related, exercise-induced, and gastroesophageal reflux-associated asthma. Further complicating matters is that there is a significant degree of overlap between the two primary categories of asthma, with some people one day clearly having stimuli-evoked asthma and on another day experiencing an attack for no apparent reason.

 

 

For some asthmatics, we cannot readily determine what's triggering their asthma, despite extensive testing. These asthmatics are called "idiopathic" or "idiosyncratic." True idiopathic asthma is becoming a rarity as we learn more and more about asthma. For most idiopathic asthmatics, time, coupled with some detective work, will ultimately reveal what triggers their attacks.

 

Conventional and Integrative Approach—Extensive testing, asthma diary review, and complete evaluation of home and work environments is needed to identify offending agents. The conventional approach uses medications like albuterol and inhaled steroids to manage symptoms. The integrative approach employs a variety of natural remedies and non-pharmacological treatments to reduce bronchoconstriction and inflammation.

 

 

In allergic asthma an allergen, such as dust, pollen, or cat dander, is triggering the attack. It is estimated that 50 to 80 percent of asthmatics have an allergic component to their asthma. What triggers the attack varies from person to person and can change over time; however, most of these allergens are airborne. Inhaled allergens are potent triggers in susceptible individuals and can produce an immediate asthmatic response that may be followed by several weeks of increased airway reactivity. Many people who develop asthma from airborne allergens at first require large amounts of allergen to provoke a reaction. Over time, as the person becomes sensitized, smaller and smaller amounts of the offending allergen are needed to trigger a response.

 

Many people with allergic asthma only have symptoms during a particular time of the year, such as the spring when pollen counts are high. In fact, when there are high pollen counts, hospitals frequently record elevated numbers of asthma-related emergency-room visits and deaths. Other people can exhibit allergic asthma year-round if they happen to be allergic to stimuli like animals, feathers, or dust mites.

 

Most people with allergic asthma have an almost immediate reaction to the offending allergen, called the "acute response." Approximately 30 to 50 percent of acute responders will experience a "late response" six to ten hours later. Some people never experience the acute response and only develop the late response to a particular allergen. As with most asthma triggers, the best way to treat allergic asthma is to avoid the allergen.

 

 

If anything gets an asthmatic in trouble, it's a viral infection. In fact, viral infections are perhaps the most common triggers of an asthma exacerbation and some asthmatics only have symptoms during and after a cold. Parainfluenza and respiratory syncytial viruses cause the most trouble for children, whereas influenza and rhinovirus are the usual suspects in adults. Rhi-novirus is the bug often responsible for the common cold. Viral infections cause damage by increasing airway inflammation and sensitivity, which in turn can worsen asthmatic symptoms for weeks to months.

 

Conventional Approach—Good old-fashioned prevention and healthy living is the best remedy. Treatment relies primarily on relief of symptoms, with acetaminophen for fever and pain coupled with liberal bed rest and fluids.

 

Integrative Approach—As in Western methods, prevention is the key. One to two grams of vitamin C daily may help you avoid the common cold.

 

 

While allergies and infections have traditionally shared the blame for the vast majority of asthma attacks, emotions have increasingly been recognized as playing a major role. Attitudes and emotions can cut both ways, making or breaking your asthma. It's good news for asthma control if you have a positive attitude, bad news if you have a negative attitude. It is estimated that half of all asthmatics have an emotional component to their condition. Some individuals can make their symptoms better or worse just by thinking about them. There are even a few asthmatics who can consciously modify their airway response to inhaled stimuli.

 

 

Almost any drug can cause an asthma attack in a susceptible individual; however, the most common offenders are aspirin and beta-blockers. Beta-blockers are medications commonly used for glaucoma, high blood pressure, and heart problems. They are given to asthmatics only under the most unusual of circumstances. Aspirin is a notorious and potentially dangerous asthma trigger, especially in individuals with nasal polyps. Other common medicines that can cause trouble for asthmatics are nonsteroidal, anti-inflammatory drugs (NSAIDs), such as ibuprofen. Included in this group are over-the-counter agents like Advil, Aleve, Motrin, and naproxen. It is believed that NSAIDs exacerbate asthma by blocking cyclooxygenase, leading to increased leukotriene production.

 

Drug allergies are especially dangerous for the asthmatic since medications are taken internally where they can have a maximal effect, in rare instances causing death. This does not mean that asthmatics can't take these medications. Only about 10 percent of asthmatics are allergic to aspirin. Acetaminophen (Tylenol) usually does not cause problems for asthmatics. Most of you probably know by now what medicines and foods you can eat and those you cannot. If you've been taking ibuprofen without any problems for the last twenty years, now is not the time to stop. If, however, you have never taken aspirin, now is not the time to start. If in doubt, check with your doctor to see if the medicine you are taking (or about to take) is safe.

 

Food allergies can be caused by the food itself or by something artificial in the food, like a food coloring or preservative. Food colorings are used virtually everywhere, so it's important to read food and drug labels to see if food coloring is present. Sulfiting agents, another common allergy trigger, are used as preservatives in medicines and food. Common sulfiting agents include potassium bisulfite, potassium metabisulfite, sodium bisulfite, sodium sulfite, and sulfur dioxide. Sulfites can hide anywhere, from the salad bar to your favorite wine, and are even present in some asthma medications, like intravenous steroids and inhaled agents. This, in part, explains why you hear about the rare asthmatic who gets worse with treatment. If you find that you feel worse after using an inhaled asthma medication, check with your doctor to see if it contains sulfites.

 

It is estimated that 1 to 2 percent of adults and 8 percent of children have food allergies, a number that is probably higher in asthmatics. One study reported 29 percent of asthmatics as having "clinical sensitivity to food." Testing for food allergies can employ various methods, including the "scratch-and-prick" technique to a food elimination diet.

 

There is limited evidence that a "hypoallergenic diet" may help asthmatic infants; one study reported that "90 percent of infants with allergic rhinitis and/or bronchial asthma improved on a hypoallergenic diet." Hypoallergenic diets rely on "prolonged" breast-feeding with the mother avoiding cow's milk, eggs, and fish for three months. Studies on hypoallergenic diets in adults remain mixed; however, there seems to be a consensus that food allergies should be considered in asthmatics. One report from the Colorado Allergy and Asthma Center recommends that "the workup of food allergy in asthma should be considered in patients in whom asthma is poorly controlled despite persistent use of appropriate asthma medications."

 

 

Many authorities blame the asthma epidemic on increasing levels of air pollution, especially indoor air pollution. There is little doubt that the air we breathe has become more toxic over the past thirty years. Air pollution is a leading airway irritant, and the number of hospital visits for respiratory illness increases predictably and dramatically as air quality deteriorates. This is especially true on hot, humid days or days when there are thermal inversions (which occur when a layer of cold air is trapped under a layer of warm air). While the list of asthma irritants is extensive, ozone, nitrogen dioxide, and sulfur dioxide are the greatest offenders.

 

 

While I believe that work is good for you and builds character, for some asthmatics work is the cause of their trouble. Many people have occupational asthma without even knowing it. The occupational asthmatic feels fine at the start of the work week, only to have their symptoms progressively worsen over the course of the week. They often feel a little better when they go home, but their symptoms recur once they return to work the next day. Most commonly, occupational asthmatics feel best over the weekend or after a vacation, but as soon as they go back to work, their symptoms return.

 

The number of occupational asthma triggers is extensive and can range from wood or metal dust to chemical fumes to grains and herbs. Talk to your doctor if you have contact with any of these substances or notice that your asthma gets worse at work but better when at home.

 

 

People with exercise-induced asthma (EIA) typically complain of wheezing and shortness of breath after exercise. While there was once debate over whether individuals with EIA were really asthmatic, it is now generally believed that people with EIA have subclinical asthma, which will ultimately develop into chronic asthma provoked by stimuli other than exercise. It is estimated that over 70 percent of asthmatic children have EIA. Unlike allergic or infectious asthma, EIA does not result in residual airway hyperreactivity. In other words, once the EIA attack has resolved, airway reactivity returns to normal. Another difference between EIA and typical asthma is that bronchial smooth-muscle contraction does not appear to contribute to EIA. Rather, researchers suspect that the extreme temperature difference between the relatively cold, dry inhaled air and the moist, warm lung tissue causes reflex-induced lung congestion. There is, however, evidence that EIA and regular asthma may be more similar than previously thought, as one 2002 study demonstrated when it found that eosinophil levels correlated to the severity of EIA.

 

In large part, EIA symptoms depend on the conditions under which exercise is performed. In general, the higher the ventilatory rate, the more severe the EIA. For example, EIA is more likely to occur during running rather than walking. Also, the colder and dryer the air, the more likely one will experience EIA. This is why some asthmatics have trouble with winter sports but feel fine while swimming in a heated indoor pool.

 

 

This is an asthma subtype not seen in many medical textbooks, however, there is an increasing body of evidence implicating gastroesophageal reflux disease (GERD) as an important player in asthma, especially asthma that is worse at night. GERD occurs when acid from the stomach finds its way up into the esophagus. Researchers suspect that this esophageal acid induces a nerve-mediated reflex that results in bronchoconstriction. An alternative theory is that this acid is aspirated into the lungs, where it causes asthmalike symptoms. Whatever the mechanism, it is estimated that 50 to 80 percent of asthmatics have GERD, although there is presently a controversy over how much asthma is caused by GERD. The interesting thing about GERD is that it doesn't always cause symptoms like heartburn. Apparently most people experience some degree of reflux, but why some individuals develop symptoms whereas others don't remains a mystery.

 

There are multiple studies on the relationship between GERD and asthma. One study from Iceland, published in Chest in 2002, examined 2,661 individuals, ranging in age from twenty to forty-eight, from three European nations. The study found that those patients who had GERD were 2.5 times more likely to have wheezing and almost 3 times more likely to have shortness of breath at night, when compared to people who did not have GERD. The authors concluded that "the occurrence of [GERD] after bedtime is strongly associated with both asthma and respiratory symptoms." Another study examined fifty-two children with various respiratory symptoms and found that in 42.2 percent of these patients, GERD was the cause of their chronic respiratory symptoms. A group of Italian researchers summed up the link between GERD and asthma, writing that "in patients with asthma, nocturnal [GERD] has been associated with triggering and worsening bronchoconstriction. There are data to suggest that the prevalence of [GERD] is higher in patients with asthma than in the general population and that [GERD] is directly associated with asthma severity."

 

Even more remarkable, there is a substantial body of evidence demonstrating that some asthmatics will have their asthma "cured" following anti-reflux therapy. One French study followed forty-four patients with severe asthma who had their GERD treated surgically. The authors reported that 25 percent of these patients experienced "total cure" of their asthma and another 16 percent experienced "marked improvement." Another study, which examined 324 patients who had GERD-related asthma, chest pain, cough, and hoarseness, found that 94 percent reported improved symptoms and 48 percent had their symptoms resolve following surgery.14 Children may have more to gain from reflux surgery, considering one study of 132 children and adults found that 78.6 percent of the children had their respiratory symptoms disappear after surgery compared to 36 percent of adults.

 

If you have severe asthma with GERD, surgery is an option you may want to investigate. Further studies on medical versus surgical management of GERD in asthmatics are underway. How much GERD actually contributes to asthma will probably remain a subject of debate for some time; however, if you find your asthma symptoms are particularly worse at night, consider the possibility that GERD is playing a role. A trial of anti-reflux therapy may be warranted, so talk to your healthcare provider about your concerns and treatment options.