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Posts Tagged ‘Asthma’

Questions and Answers

1. Is it possible or desirable to have an additive-free diet?

You can avoid food additives in the U.S. by eating at restaurants that say “no food additives” and buying natural, unprocessed foods for the home. Generally, however, people are anaphylactic to only one particular substance. If they can figure out what that is, they can avoid just that substance specifically; they don’t have to strive for an additive-free diet.

2. Are additives in general harmless unless one has a specific allergy to them?

That is correct. The Food and Drug Administration has a list of additives that are considered to be safe. Those have no obvious problems associated with them, unless one looks at a particular group of people who have an unusual sensitivity to a particular chemical.

2. How do asthmatics respond when they eliminate sulfites from their diet?

They do not generally improve, because only five to 10% of asthmatics are in fact sulfite-sensitive, and they are of necessity already avoiding sulfites because otherwise they would be having reactions all the time; the remaining 95% will not notice any difference at all.

3. Are there any potentially dangerous additives that might not be labeled?

In the U.S., I would say no. It’s fairly well covered.

4. Are there any additives that might appear on labels under confusing code names or numbers?

The commonest confusion tends to arise in the case of monosodium glutamate, which often appears on labels as hydrolyzed vegetable protein, or added hydrolyzed something-or-other, but not as MSG. In addition, some colourings appear under the name “natural colours,” though they may provoke hypersensitive reactions in some people. The term “artificial colouring,” or “other approved FD&C dyes,” may also appear in place of the actual name of the dye used. The dye Yellow No. 5 (tartrazine), for example, must be named specifically, but there are other individual dyes for which no such regulation exists.

5. Does the food or drink make any difference in how the additive affects the system? Is there any difference between equal doses of sulfites in a potato salad and in a carbonated drink?

When sulfites are present in a liquid or gas medium, then it’s much more likely that they will be inhaled by an asthmatic and provoke a reaction. If it is actually a constituent part of the food, for example if it is bound to a potato, then it’s much less likely to escape as sulfur dioxide. Of the five percent of asthmatics who are sulfite-sensitive, probably 95% would have no reaction to the potato, whereas they would be much more likely to react to the sulfites in a carbonated drink.

Glossary:

Urticaria: Commonly known as hives, this is a temporary skin condition marked by pale, patchy swelling and itching.

Angioedema: A flushing and swelling of the skin caused by the effusion of fluids into the tissue.

Anaphylaxis: A general, rather than local, allergic reaction characterized by difficulty breathing, wheezing, a shock-like state, or any combination of these symptoms.

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There have not been many rigourously controlled studies in the area of additives and allergy, and so much of the evidence for specific links between substance and reaction is anecdotal. Those additives that have most often attracted the attention of investigators can be grouped into about seven substances or families of substances: dyes, parabens and benzoates, BHA and BHT, nitrates, aspartame, MSG (monosodium glutamate) and finally, sulfites.

Sulfites are used heavily in both foods and beverages for their ability to inhibit certain enzyme reactions. It’s the enzyme reaction that causes an apple or an artichoke to turn brown when it is cut, that blackens mushrooms and causes spots to form on fresh shrimp. Sulfite also prevents browning that is caused by non-enzymatic reactions in wine, dried fruits, vinegar and other products and is used in particularly large quantities for this task. Because sulfites are also antioxidants they are used by many pharmaceutical companies in drugs such as Novocaine, Demerol, thorazine and some brands of eyedrops.

Sulfur dioxide is a known irritant for asthmatics, but heat or acid — such as the gastric acid in the stomach — cause sulfites to release sulfur dioxide. For that reason, the U.S. Food and Drug Administration (FDA) requires the declaration of sulfites on food labels if they make up more than a certain proportion of the contents. The FDA also banned the use of sulfites on fresh vegetables, for example, in salad bars where it was once common.

Benzoates such as benzoic acid and sodium benzoate are widely used as preservatives in food and beverages for their antibacterial qualities. Parabens, similar preservatives, are used more in drugs and cosmetics. The worldwide consumption of benzoates, used since the early 1900s in food, is over 10 million pounds. Benzoates have low toxicity, and in fact occur naturally in prunes, cinnamon, cloves, tea, anise and many berries.

Monosodium glutamate is an amino acid commonly used as a flavouring. While it appears naturally in some foods like Camembert cheese, it’s used mainly as an additive, particularly in Chinese and Japanese food. A single bowl of Wonton soup can contain 2.5 grams of MSG. It’s also one of the “secret herbs and spices” in Kentucky Fried Chicken.

Aspartame (NutraSweet) is another additive that enhances flavour. Temporarily banned in the mid-1970s because of fears that it caused mental retardation and endocrine dysfunction, aspartame is now back as a common additive in foods and carbonated drinks. Nitrates and nitrites are preservatives that also add colour and flavour, and are common in preserved meats such as salami. Butylated hydroxanisole (BHA) and butylated hydroxytoluene (BHT) are antioxidants that appear in many grain and cereal products.

Dyes used in foods are either coal-tar derivatives called azo dyes, the best-known of which is tartrazine, or dyes derived from other sources known as non-azo dyes.

Allergic reactions: Urticaria, angioedema and anaphylaxis

Tartrazine and other dyes, benzoates and parabens may aggravate urticaria at times but none of them have been shown to cause it. Parabens have been shown to cause an anaphylactic reaction on a few rare occasions, but never when taken orally. Sulfites also have been known to cause anaphylaxis. MSG is responsible for an allergic reaction known as Chinese restaurant syndrome (CRS), characterized by headache, nausea, chest tightness, sweating and a burning sensation along the back of the neck. The symptoms affect only MSG-sensitive individuals who eat free MSG (usually added in the restaurant as a condiment) on an empty stomach. MSG has also been blamed in a case of angioedema. Aspartame, BHA and BHT are all known culprits in isolated cases of urticaria.

Allergic reactions: Asthma

The exact mechanism by which sulfites cause asthma attacks is controversial, but it has been suggested that inhalation while swallowing sulfite-bearing foods is the cause. This seems borne out by tests in which sulfite-sensitive people with asthma swallowed sulfite solutions with no reaction when they held their breath. Anyone can develop sulfite sensitivity, and many people’s first experience with asthma was a reaction to sulfites, which over the course of a few months became chronic asthma with dependence on corticosteroids. About three to five percent of asthmatics are sulfite-sensitive, and they tend also to be susceptible to other irritants such as exercise, upper respiratory infections, and particularly smog. Any food containing sulfites in sufficient concentration to cause a reaction must now be so labeled under FDA rules in the U.S.

MSG and benzalkonium chloride can cause bronchial constriction in asthmatics, but cases are rare and in the case of the second additive, concentrations are usually too low. Spearmint, peppermint and menthol, which appear in chewing gum and toothpaste, are also capable of triggering an attack. Dyes, parabens and benzoates are not believed to be dangerous for people with asthma.

Ragweed pollen allergies are very common in our population. Sufferers have to depend upon medication to help them manage the symptoms of irritated eyes and nasal passages. Topical intranasal corticosteroids have been a popular choice of medication for seasonal allergic rhinitis; the most recent of these is fluticasone propionate (Flovent).

This new drug is thought to be a safer choice of treatment because it has little effect on other body systems when it is given in doses of up to 16 mg daily. Thus it is seen as having a good safety profile and as being effective in controlling allergy symptoms. The study compared the effectiveness and safety of treating seasonal allergic rhinitis in adolescents using fluticasone propionate (Flovent) versus the use of loratadine tablets, another drug traditionally used in such therapy.

The authors compared the nasal and eye symptoms of 240 adolescents suffering from ragweed-induced allergies, half of whom received fluticasone propionate (Flovent) nasal spray at 200 g daily while the rest were given loratadine tablets, 10 mg daily. Loratadine is an antihistamine which demonstrates little sedative and dehydrating side effects. Patients were asked to record their nasal and eye symptoms on a daily basis.

Overall, fluticasone propionate provided more symptom-free days than did loratadine for nasal problems, but there was no difference between treatments in terms of relieving eye symptoms. Both drugs had the adverse side effects of headache and sore throat. An interesting observation was the diurnal variation in symptom levels, with the morning being the best time of the day for allergy sufferers, regardless of treatment.

Based on these findings, researchers have concluded that fluticasone propionate (Flovent) is an effective means of controlling the symptoms of this specific allergy, without extreme side-effects, and suggest that this treatment be recommended as a first choice for ragweed allergy sufferers.

Questions:

1. Do adolescent allergy sufferers differ from adults? Do allergies intensify with age?

In the case of allergic rhinitis, children and adults are affected in the same way. Allergies do increase with age, due to accumulated exposure to allergens – you can’t be allergic to something you’ve never been exposed to. Very young children tend not to have respiratory allergies (excluding asthma) – these often develop around age six or seven. Both the number of allergies and their intensity generally increase until age 20 or so, then may start to gradually subside. I’m referring to hayfever, not asthma. Of course, people can become allergic to anything at any age.

2. Are there any side effects associated with long-term use of topical intranasal corticosteroids?

Side effects are related to dosage: low doses are well tolerated, but higher doses can cause thinning skin and increased bruising in the elderly, and can interfere with growth in children. They may occasionally lead to yeast infections in the mouth. That’s why we keep patients on the lowest dose possible and follow them carefully. However, 95% of patients have no side effects at all.

3. Do you recommend that people take inhaled corticosteroids only when symptoms arise, or as a preventive measure?

We only prescribe them as needed, never preventively, and at the lowest possible level for effective symptom control.

Comment: I think the most useful development in hayfever treatment in the last 30 years has been the introduction of inhaled corticosteroids. Seasonal use for limited periods (one or two months at a time) is very safe, and the most effective way of keeping symptoms under control. In my practice, every patient who’s troubled by acute ragweed allergy symptoms will get inhaled corticosteroids. However, these must be combined with efforts to minimize exposure to allergens. In the case of ragweed, there’s nothing you can do while outdoors, but at home, keeping windows closed is very important. Air filters are useless if outside air full of pollen is continually coming in. Air conditioning may be needed, with the vents kept closed. This will not only reduce the pollen count, but also the humidity. More people in damp houses are affected by respiratory symptoms, because of increased mould and dust mites. Air conditioning helps both factors.

Researchers believe they’ve developed a way of disabling the process that triggers symptoms in patients with allergic asthma. If so, some allergic asthmatics may find relief of symptoms and possibly be able to reduce their need for corticosteroids, currently the mainstay of treatment for many asthmatics.

In order to understand the role of IgE (immunoglobulin E) in allergic asthma, it might be helpful to picture a string of dominoes. Think of an allergen (pollen, pet dander, cigarette smoke, etc.) as the first domino. For those with allergic asthma, exposure to an allergen tips that first domino, initiating a chain of events that results in respiratory distress. In this scenario, IgE would be the second domino after inhaling an allergen, because the person with allergic asthma produces specific antibodies for each allergen. These IgE antibodies bind with mast cells and basophils, triggering the airway inflammation associated with asthma.

Researchers believe if they can stop this process, symptoms of allergic asthma will be reduced. A recent study conducted by researchers from the National Jewish Medical and Research Center in Denver, Colorado, tested this theory with encouraging results. They used a treatment known as recombinant humanized monoclonal antibody (rhuMAb-E25) that binds to IgE, preventing it from interacting with mast cells and basophils.

These researchers studied 317 patients with allergic asthma severe enough to require inhaled or oral corticosteroids (or both). Patients were given either high- or low-dose rhuMAb-E25 intravenously or a placebo for the duration of the study, with doses being given at the beginning of the study, on days four and seven, and then once every two weeks for 20 weeks. Patients continued with their usual corticosteroid regimen for the first 12 weeks of the study, tapering and attempting to discontinue them during the last eight weeks of the study.

Patients receiving the rhuMAb-E25 had less severe asthma symptoms at 12 and 20 weeks, and more patients receiving it were able to decrease or discontinue corticosteroids than in the placebo group. These researchers believe that rhuMAb-E25 is a promising new approach to the treatment of allergic asthma.

It’s as plain as the runny nose on your face and the clump of tissues clutched in your hand – or is it? You’re 50 years old and for some reason, you’ve entered the world of sniffles, coughs, rashes and wheezes.

More than likely you are dealing with allergies or asthma. And while you may not have had problems ever before, your immune system at 50 is not what it used to be.

“Age is not the only factor, but it can contribute to an increase in allergies and allergy-induced asthma,” says Dr. Mark S. Dykewicz, associate professor of Internal Medicine and training program director, Division of Allergy and Immunology, St. Louis University School of Medicine. “The simple truth is as we get older our immune system begins to break down.”

Dr. Dykewicz says asthma and immune response are tightly intertwined. Immune responses in the form of allergic reactions trigger attacks in about half of the adults with asthma. And to a large extent, immunologic events determine the degree of inflammation that will accompany allergic reactions and thus the severity and duration of asthma attacks.

“Although sometimes mistakenly viewed as a trivial disease, symptoms of allergic and non-allergic rhinitis (hay fever) may significantly impact a patient’s quality of life by causing fatigue, headache, cognitive impairment and other systemic symptoms,” Dr. Dykewicz explained.

Some people over 50 had asthma when they were children or young adults, and now the problem has come back. In two studies by the American Lung Association, more than a quarter of the people over 65 had some form of wheezing, a common symptom of asthma. There may be wheezing with or without colds, or there may be attacks of shortness of breath with wheezing. And you can have asthma even if you don’t wheeze.

It is often difficult for a doctor to decide whether the problem in a patient over 50 is asthma or another lung disease. Other lung diseases that cause similar problems are bronchitis and emphysema, especially in people who smoke. Older people who are allergic to pollen, pets or dust are at higher risk of developing asthma too. Heart disease may also cause breathing problems, and a person can have heart and lung disease at the same time.

Asthma diagnosis in the young is facilitated by a relative scarcity of other conditions that mimic asthma or complicate its clinical presentation. In the elderly, however, the differential diagnosis of episodic chest symptoms expands as cardiovascular disease and other forms of chronic lung disease become more prevalent.

So what is asthma? Simply put, asthma is a physical problem that makes it more difficult to breathe. When you inhale, air comes in through your nose, and it passes down the bronchial tubes to your lungs. When you exhale, stale air from your lungs exits through the same tubes. But when you have asthma, the breathing tubes are sensitive. They react to smoke, pollen, dust, air pollution allergies and/or other triggers. The breathing tubes respond by becoming tight, inflamed and swollen, and that makes it harder to breathe.

The allergic response is a defensive reaction of the immune system against allergens, which are innocuous substances that the body interprets incorrectly. The body mistakenly identifies substances such as pollens, animal dander, foods, insects and their venom, and some medications, as dangerous.

Symptoms vary widely because different allergens stimulate the immune system at different sites in the body. The respiratory system is the most common site of allergic reactions. Allergens in the upper airways cause sneezing and nasal congestion, while lower airway distress includes bronchoconstriction and wheezing.