Written by Prof. Eugene Weinberg, Dr Gloria Davis and Prof. Paul Potter
© Allergy Society of South Africa & SACAWG
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Introduction
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Allergy is a serious and increasing problem but our understanding of these problems has increased enormously over the past 20 years. Therefore one can be very optimistic about the outlook for allergic sufferers these days and there is no need to be over-concerned if you have an allergy.
The word allergy has two Greek roots: “allos” meaning altered and “ergos” meaning work. With allergy we experience an altered reactivity. Allergy is one of a series of immunological defences that our body has to protect us against bacteria, viruses or parasites. Unfortunately, this protection sometimes harms us as well. Then we get allergies.
Allergens are the substances that may cause these reactions. Examples are pollens from trees, grasses and weeds, animal allergens such as arise from cats or dogs, housedust and especially house-dust mites, insect parts and insect stings, foods additives, fungal spores and even certain medicines such as aspirin or penicillin.
We make contact with these allergens by breathing, eating and touching them. Once in the body the allergens encounter mast cells and other specialised cells. These cells belong to a group of cells that act as soldiers of the body�s immune system. They line the areas of our group of cells that act as soldiers of the bodies that are in contact with the outside world, the skin, nose, lungs and digestive systems.
The surface of mast cells are covered with specific antibodies called IgE (Immunoglobulin E). When a mast cell encounters an allergen such as house-dust mite and has the specific IgE for this allergen on its surface, a series of complex biochemical reactions occur within the mast cell will result in the secretion of granules containing chemicals such as histamine. These chemicals known as “mediators” are the substances which cause allergic damage, especially swelling and inflammation.
It is now recognised that in the majority of asthma sufferers, certainly in virtually all children, the inflammation of the lining membrane of the airways is caused by an allergic reaction. Other factors such as viral infections, exposure to pollutants, cigarette smoke, mist and cold air and certain forms of exercise may also provoke the same reaction and result in airway inflammation. Certain occupations carry an increased risk for adult asthmatics. These include bakers, veterinary surgeons, spray painters and wood-workers.
How is the diagnosis of allergy made?
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There are several ways to determine whether a person with asthma is allergic. This is usually through the doctor taking a carefully history, conducting a screening test (Phadiatop) and then doing skin tests or RAST to find out which allergens are affecting the sufferer.
What can be done about allergies and asthma?
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There are a number of approaches to the treatment of asthma. The most important one aims at the complete removal of the allergen where at all possible. The elimination of allergy-producing house-dust mites, the removal of a dog or cat or a feather pillow are simple examples of removing the offending problem. Some younger children may benefit from the avoidance of certain foods such as milk. All asthmatics should avoid known preservatives such as sulphur dioxide.
Your doctor will be able to provide you with excellent advice about avoidance programmes. Printed guidelines are widely available through the Allergy Society of South Africa and you should request these from your doctor. The more knowledge you have about avoidance programmes the better the outlook will be for the treatment of your asthma. Certain occupations carrying a high-risk of allergic sensitisation should not be recommended for young asthmatics about to embark on a career.
In addition to avoidance procedures there is a wide-range of highly effective medicines to treat all grades of asthma. In the vast majority of cases there is absolutely no reason why people who have asthma should not be able to lead a normal, active and happy life these days.
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Part 2: Indoor Allergens
Part 3: Pollen and Asthma in South Africa
Copyright: Allergy Society of South Africa.
Written by Prof. Eugene Weinberg, Dr Gloria Davis and Prof. Paul Potter
Endorsed by ALLSA.
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ALLSA P.O. Box 88 Observatory, 7935 Cape Town, R.S.A. |
 Common Duiker Background: Nyala |