Is Asthma Preventable?
Some of the proudest achievements in the history of mankind concern the eradication of the disease. Good housing and cleanliness have helped us wipe out the plague, vaccination has eradicated smallpox, insecticides have helped control malaria. Could the same happen for asthma? or Is Asthma Preventable? Our present understanding of asthma suggests the answer will have to be, 'probably not'. But there is a lot we can do to avoid getting asthma and there is always a hope around the corner of exciting research developments.
Asthma and Allergy
Is Asthma Preventable? One important cause of asthma is an allergy. To have an allergy means that you are oversensitive to something we all encounter in our daily lives but which causes most people no upset at all. A very common allergy is 'hay fever'. This is a sensitivity of the nose and eyes to grass pollen floating in the air from late May through to July. The allergy takes the form of sneezing, watering of the eyes, running and often blockage of the nose. Attacks of asthma can also be due to allergy. It will most often be an allergy to something we take into our lungs from the air we breathe. It could be grass pollen: some sufferers from hay fever get asthma as well. But it can be a lot of other things - other pollens, household dust, animal fur, and skin particles and so on.
How to Avoid Allergies?
Sometimes it is possible to avoid allergic substances so effectively that asthma ceases to be a problem. Some asthmatics are highly sensitive to cats or dogs but to very little else. If they avoid all contact with these animals, they will have very little trouble from their asthma. Avoiding pollen is less easy. Moving away from grass pollen areas at the appropriate time of year is rarely possible. Other less drastic steps will help: staying indoors on dry, windy summer days, keeping away from long grass, closing the car windows when driving in the country and keeping your bedroom windows closed at night. Attempts have been made to give hay fever and summer asthma sufferers their own especially clean environment to breathe by using plastic helmets, rather like huge inverted goldfish bowls. They are not very effective and most people who have tried them feel pretty ridiculous wearing them! Can household dust be cut down to such an extent that dust sensitive asthmatics are improved? In some instances, the answer is almost certainly 'yes', but it requires almost superhuman devotion to cleanliness to achieve this result. Simple measures to cut down the dust - or rather that special component of dust that seems so important for asthma: the minute house dust mite - are these. Wrap your mattress in cling film plastic sheeting: change and wash your pillowcases, sheets, and duvet covers weekly: get rid of feather pillows and eiderdowns and woolen blankets, and replace them with synthetic ones, which must be washed regularly. Remove carpets, animals and soft toys from the bedroom. Leave to other people the housework that involves vacuum cleaning. These measures do seem to help some asthmatics, but dust-mite allergy may not be your only problem and you have to recognize that it is very difficult to rid a house completely of dust, so you must not be disappointed if, despite all the effort, your asthma is not better. There are, of course, plenty of safe treatments to control it, which are described later in this pamphlet. Two other possibilities for avoidance need considering: dust and fumes encountered only at work, and food and drink allergy.
Asthma which only occurs at work or in a certain environment is special for two reasons. The first is that various industrial processes can cause dust and fumes that we rarely, if ever, encounter in everyday life, to leak into the air of the workplace. They can be found in quite high concentrations and can cause a number of workers in the area to develop asthma. Certain fumes created in the plastics industry or in the manufacture and use of glues and paints are typical examples. The second point about occupational asthma is more important. Once the problem has been recognized, it is nearly always possible by using standard procedures of industrial cleanliness to eradicate the dust or fumes and so prevent anyone from developing asthma.
Asthma that is caused by food or drink is not common, but it does occur and, once recognized, the cure is simple: avoid that item of food or drink. Some reactions are quite startling with general skin allergy as well as asthma: certain fruits, shellfish or nuts can do this. These reactions are obvious and it is usually easy to avoid the offending food. If asthma is brought on by something we eat every day, then finding the cause is not so easy and avoidance can present problems. Certain colorings (especially orange and yellow) and food additives can cause asthma, and this may go with sensitivity to aspirin or other pain killing tablets. If it seems that this is your problem or if dairy products, eggs or other common food items might be responsible for your asthma it is best to consult your doctor or see a dietician about a proper diet rather than experimenting with eliminating these foodstuffs yourself.
Avoidance in Other Sorts of Asthma
Avoidance does not seem to be practical or to help very much in other sorts of asthma. It was once suggested that breastfeeding prevented the babies of allergic or asthmatic parents from developing allergies. It may help eczema but it does not really seem to have much effect on asthma. Quite a lot of asthma is triggered off by colds and chest infections. The way most of us live our lives makes it quite impossible to avoid catching colds. In some people, asthma is made worse by stress. Coming to terms with life's difficulties and strains can certainly help a few asthmatics, but asthma is rarely due to stress alone.
Though smoking is not a direct cause of asthma, it does seriously damage the breathing tubes of the lungs and so aggravates asthma. Also being asthmatic makes smoking itself more dangerous. The message is simple. Don't smoke.
Are there other approaches to prevention? For many years a hope has existed that allergic subjects could be made less sensitive by a course of injections to 'desensitize' them. This means giving at first a very, very weak solution of the pollen or dust causing the allergy and then, usually at weekly intervals, increasingly stronger solutions. It was hoped in this way to build up a tolerance. For some allergic subjects, it was quite successful. The severe reactions that can follow bee and wasp stings are a case in point. For hay fever benefit often followed, but for asthma, results were usually less encouraging. And regrettably, the injections themselves can cause side effects. In a very small number of cases, these side effects have proved fatal. Though the risk is very small, the fear of this outcome has meant that few doctors are now prepared to give or advise these injections except when, as with bee and wasp sting allergy, the benefits are undisputed and the condition itself can be fatal.
Prevention Through Treatment
Finally, we come to the very effective ways in which the symptoms of asthma can be prevented by the use of asthma treatments. This is referred to in our pamphlets as protective treatment and in medical circles often as prophylactic treatment. These treatments when taken seem to have no obvious immediate effect but suppress asthma symptoms. When taken regularly they gradually build up protection against many of the triggers of asthmatic symptoms. The first introduced protective treatment was Intal, the most often used now are the steroid inhalers and there are also more recent treatments available.
Intal or Disodium Cromoglycate
This was introduced in the early 1960s after tests had shown that it could protect against allergic asthma. Taken by someone allergic, for example, to cats, before entering a room or house with cats in it, it will prevent asthma developing. Taken through the summer months it will prevent pollen sensitive asthmatics developing summer wheezing attacks. For other asthmatics allergic to many things in the environment it can be taken continuously and can be very effective especially in children with allergic asthma. It also works in some adults even when there appears to be no obvious allergy involved. Intal also protects against exercise-induced asthma. lntal is still often used as a first line protective treatment for children with allergic asthma, but for many other asthmatics, it has been replaced by the steroid inhalers.
As with other protective treatments, the taking of a puff or two of a steroid aerosol seems to have no immediate effect. However, once it has been taken regularly for a few days or a week or so, many of the symptoms of asthma improve. Night time awakening with cough and wheeze is less, morning tightness is less, day time wheezing with cold air or exercise improves and even chesty colds are tolerated better. The steroid inhalers have now become the mainstay of our treatment of asthma since they provide excellent protection. Different doses are available to suit different needs and different devices are available to ensure proper delivery of the treatment into the lungs. There are more details about steroid aerosols in our pamphlet 'Steroid Treatment for Asthma'. The commonly used steroid aerosols are beclomethasone (Becotide, Becloforte), betamethasone (Bextasol) and budesonide (Pulmicort).
Other Protective Treatments
Another inhaler which gives protection to asthmatics was introduced at the end of 1986. This is Tilade (nedocromil). It has an effect partly like Intal and partly like the steroid inhalers but works quite differently from either of them. It is too soon yet to say which asthmatics will benefit most from this treatment: time will tell. Though inhaled medicines are usually better than tablets for asthma, some people cannot take inhalers properly and others have allergies also in the nose or elsewhere. For these, it is useful to have an anti-allergic treatment that can be taken by mouth and so be of benefit to all parts of the body. Antihistamines, like Piriton or Triludan, work well for hay fever and some other nose allergies but are not of much use for asthma. Zaditen (ketotifen) is like the antihistamines but also works in other ways that help some asthmatics. Unfortunately, like some antihistamines, it causes drowsiness and this makes it a difficult treatment, especially for adults, to tolerate. Finally, it is occasionally possible to use the bronchodilators-the relieving treatments - in a protective way. The best example is the use of a puff or two of a bronchodilator to protect against exercise-induced asthma. It needs to be taken just a minute or so before playing a game of going out for a run.
A great deal of research is underway at the moment to improve our understanding of what causes asthma. This will lead in its turn to better treatment, especially better protective and preventive treatment. The National Asthma Campaign will keep you up to date with any developments through Asthma News.