By allergy the immune system reacts against a substance that it is not supposed to react against, and the reaction is often exaggerated.

The substance or object that the immune system reacts against is called an allergen. Objects containing substances that commonly cause allergy are domestic dust, animal hair, household chemicals, chlorine, microorganisms, pollen, nuts, citrus fruits and seafood. Also bacteria and parasites can cause inappropriately strong immune reactions.

Around 20-40% of the population in the western world have some kind of allergy.

Allergic reaction can occur in all parts of the body, but usually the symptoms are most prominent in one organ system. These are the most common symptoms of allergy:

Lung and lower airways: gravity sensation, coughing, wheezing and asthmatic symptoms. Be aware that certain combinations of food intolerance and exertion can cause allergic symptoms in the lower respiratory tract

Nose: density, rinning nose, itching and sneezing.

Eyes: redness, itching, tears, engorgement in the eyelids

Throat: itching, mucus, engorgement or other discomfort.

Skin: itching, redness, engorgement, and possibly blisters.
 

General symptoms in the form of fatigue and indisposedness can often be an accompanying symptom

The total set of reactions occurring by allergy is very complicated. Many of these are the same as by normal immune reaction, even though they occur when they should not take place, Here are listed some of these reactions:

By exposure to a new substance, cells in the immune system learn to recognize that substance (allergen), and it learns to produce anti-bodies towards the substance, and a certain amount of antibodies is produced. The type of anti-bodies called IgE is the most important by allergic reactions.

IgE will glue itself to some cells in the blood called mast-cells, and stick out from the surface of these cells. By following exposures to antigens, these will attach themselves to the IgE-ends sticking out from the mast-cells. This will trigger the mast-cells to produce histamine and other signal substances. These signal substances will then spread through the surrounding tissues.

The signal substances will then trigger the walls of small blood vessels to leak fluid into the tissues and accumulate in the tissues. This will cause tissue swelling. They also will cause blood vessels to widen and thus increase the blood stream in the tissues. The consequence of this will be swelling and redness in the affected body parts. The signal substances will also make glands in the tissue produce more mucus, making symptoms like running nose and tight throat.

The new exposures to the antigens will also provoke even more anti-body production. The antibodies will also glue allergens together to bigger complexes. These complexes can clog small blood vessels and in other ways disturb the function of the affected organ.

The allergen-antibody-complexes are then recognized by the cells and other mechanisms that the body uses to collect and eliminate garbage. Eater-cells gather and engulf the complexes.

The immune system also will make enzymes that attack the antigens to break them down. Also this production is stimulated when antigens attach themselves to anti-bodies at cell surfaces. But these enzymes are not entirely specific, and can also to some extend break down components of the body’s own tissue, causing harm and disease symptoms.

In the beginning of the life of a person, the immune system has the potency to react against most substances in the body itself and the surroundings. However, there are mechanisms that learn the immune system to recognize normal substances found in the daily life in the early infanthood, and suppress the reactions against these.

If this learning mechanism is disturbed, allergy can develop. Instead of learning to suppress reaction against some common substances, the immune system learn to react against them, and them one has an allergy.

Allergy can also develop if a small child is never exposed to substances that later will be a normal ingredient of his daily life. In this case the immune system will not get the chance to suppress the reaction against this substance. Letting a small child grow up in an exaggerated clean and sterile environment can therefore cause allergies.

On the other hand, certain elements not being a port of a normal environment can cause allergies by repeated and massive exposure. Examples of such substances are chlorine.

Allergy varies according to the compound that causes the immunological reaction. An allergic condition also often implies reaction against a combination of several substances. Common substances causing allergy are: Pollen, domestic dust, mites in domestic dust, moulds and mould spores, chlorine, chemicals in soaps and cosmetics, animal hair, seafood, strawberry, fish, parasites, medicines like anaesthetics and antibiotics

An allergic condition may periodically get better or worse according to the concentration of the allergen in the environment. A typical example is pollen allergy with peaks in the pollination season of grass or treas.

An allergic person will often get symptoms from several tissues in the body, but the symptoms are often most prominent at one body part and give very specific symptoms at that site. Examples of specific conditions often caused by allergy are eczema in the skin and asthma in the lungs and lower airpipe.

Another typical allergic ailment is hay fever that causes irritation, sneezing, swelling and excessive secretions in the nose and irritation, redness and swelling in the eyes and their surroundings. Hay fever is usually caused by pollen allergy and is the most typical expression for this type of allergy.

Any organ can exhibit allergic reactions, but often the symptoms are confined mainly to one organ or organ system.

Allergy causes inflammatory reactions, and generally the symptoms seen by allergy are those of inflammations, like redness, swelling, itching, higher temperature or feeling of higher temperature in the affected body part, development of sores, oozing, higher secretion of secrets or fluids.

By allergic reactions in the respiratory system there will be symptoms like: Itching and soreness in the throat and nose cavities, swelling of the airway tissues, tight nose and airpipe, increased amount of secrets in the airway cavities and coughing. There may also be asthmatic symptoms or fully developed asthma. The main symptom of asthma is cramping that constricts the airways all the way down into the lungs (constriction of the trachea and tracholes).

By allergic reactions in the skin, there will be symptoms like: Redness, swelling, red spots, itching and soars.

To prevent allergies in an individual the best way, one must begin in early childhood.

A child must be allowed to get in contact with natural elements like earth, dirt, animals, plants, physical contact with other humans, and the like. This exposure to natural elements must occur before an allergy has developed. In this way the immune system will learn to recognize common and harmless elements, and not overreact against this later in life.

Research projects have found out that children having much and early contact with pet animals like cats and dogs have a less chance of getting allergic problems later than children not having contact with pets. This is contrary to what many people believe.

On the other hands, every person should be protected from early childhood from certain elements normally not found in a natural environment, for example chlorine, soaps and cosmetics with artificial substances, and food containing unnatural additives.

The first approach in the treatment of manifest allergy is avoiding exposure to substances causing the allergic reactions. Even though exposure to natural substances can prevent allergy, exposure to an allergen should be avoided when an allergy already has developed. Ways of doing this is:

- Avoiding food one reacts against

- Avoiding contact with animals one have an allergic reaction towards

- Keeping rooms, clothes beds and furniture well cleaned

- Avoiding use of cleaners, soaps and cosmetics with unnatural additives

- Avoiding foods, drinks and snacks with unnatural additives

- Avoiding daily exposure to chlorine and other chemicals

- In cooperation with your doctor change medicines you use that may cause allergy with others

- Avoiding growth of moulds in the environment. This is done by well cleaning and keeping the environment dry.

Children are often exposed to allergens at school, and adults are often exposed at work. Parents with allergic children must inspect the school environment and require from the school administration and teachers that practically possible environmental measures are provided to keep the school free from allergens. An employee should require the same from his employer.

If you do not know exactly everything you react against, you can try to stop exposure to one factor after another, until you feel that the allergy alleviates, and then keep this factor out of your daily life for the future.

Sometimes avoiding allergens is difficult to accomplish, or make the lifestyle to restricted to be acceptable. Then one must apply medical treatment that alleviates the allergy.

A common way of treating allergy is applying medication that block the effect of the substance histamine, and thereby alleviate or prevent the symptoms occurring when the antigen get into the body.

Another way is desensitisation treatment. By this treatment one let the body get a controlled and gradually increasing exposure to the allergens over a time period, and when this period is over, one let the body get recurrent exposure to a controlled dose at regular time intervals. By this treatment the response from the immune system from the allergens gradually decrease, partly because the immune system thereby learns to recognize the allergens as harmless, and partly because the antibodies against the allergens are used up.

By knut Holt