Allergic reactions are based on abnormal regulations in the human immune system.
In the case of a so-called immediate allergy (Type I) the following will happen:
If foreign substances (antigens) penetrate the body,  the immune system develops specific antibodies or lymphocytes, which are capable of reacting if the body comes into contact with the foreign substances again.

In the case of immunity, the clash between foreign substances and the substances produced by the body lead to protection, whereas in the case of an allergy, it responds exactly the opposite. Primarily harmless and tolerated by most people, the foreign substances may react with antibodies or sensitized cells and lead to disease symptoms. When an allergic person comes in contact with the allergy trigger (allergen) defense cells appear and the body develops antibodies on a large scale or activates T-Lymphocytes. Now the body is sensitized, but still shows no symptoms of disease. Only when further contact with the allergen takes place, for example with animal dandruff, the body reacts so that the person is aware of a reaction such as a runny nose or respiratory problems.

Simply put, you react to a particular substance because your body thinks it is a pathogen and wants to fight it just as it would an infection with cold or flu viruses. Your sneezing attacks and nasal hyperactivity that tortures you is due to the fact that a particular type of immune cell (mast cell) releases substances which are highly biologically active, especially the so-called histamine.

The clinical signs of an immediate allergic reaction - such as itchiness in the nose, a severe runny nose, watery eyes, skin irritation, gastro-intestinal disorders or shortness of breath - are a consequence of this histamine release. How come?

Histamine is only released when the mast cells are aware that you are in contact with a particular substance. Therefore, it must first be sensitized, and this happens through certain antibodies that sit on the skin of the mast cells like spikes sit on a hedgehog. These "spikes" connect themselves with the invading antigens (foreign bodies), for example with pollen,  the mast cells take notice of the foreign substance and release histamin, and your nose begins to itch for example.


The allergologist distinguishes between different types of allergies:

The type I allergies are the so-called immediate allergies, clinical examples are hay fever, asthma, food allergies and insect venom allergy. The immediate allergies have numerically the greatest importance.

The type II allergy is a very rare form of allergy where, for example blood cells can be damaged. Possible triggers of a type II allergy are medicines.

The Type III allergy represents a frequent form of medication allergy. Antibodies bind to the antigens that have dissolved in the blood, such as drugs. This creates greater concentrations, which may deposit themselves in the vascular walls of the small vessels, for example on the skin or on the kidneys, causing an inflammatory reaction. This appears on the skin in the form of a rash (mostly as small red spots) partly with damage to the top layer of skin, as well as itching.

Type IV allergy is an allergic late reaction allergy. It is the only form of allergy, where the sensitized defense cells (T-lymphocytes) proceed directly against the allergens. Whereas Type I allergens almost always have to do with protein, Type IV allergens are usually small molecular substances such as metals or chemicals. Clinically expressed, Type IV allergy is known as contact dermatitis.

Examples

In childhood years, allergies occur one after another: Atopic dermatitis and food allergies dominate the first years of life, later, the respiratory allergies such as bronchial asthma, allergic rhinitis and  hay fever "seem to be more common. Allergic reactions to flowers and grass pollens cause hay fever with sneezing attacks, watery eyes and a running or stuffed-up nose. Similar symptoms may be caused by elements in dust mite faeces but these may plague one the whole year and not only during the pollination period. The same applies to a mould allergy. One believes that pollen only flies in the spring : Except for two months - November and December -  the pollen calendar keeps a number of  unpleasant factors ready for people with allergies throughout the year. It starts in January with alder and hazel. In the beginning of February and the entire March, the air is full of  hazel pollen. Birch trees spread their pollen in April and early May and the dandelion blossoms fly almost throughout the entire spring and summer. And this goes on until November.

If the cause for an allergy remains, it can lead to a broadening of the illness: For example, hay fever can become bronchial asthma. 

Almost every second person will have an Allergy in 2010

Even two generations ago hay fever was an almost exotic disease(!) This poses the question as to the cause of the rapid growth, which has empirical evidence. As part of an extensive ISAAC study from1992 to 1996 in 155 study centers, 463,800 children aged 13 to 14 years were examined. The following figures were calculatd for the widespread allergies in Germany:

- Allergic asthma: 5 percent

- Allergic rhinitis (allergic induced rhinitis ): 15 percent

- Sensitization (against type I allergens): 30 to 40 percent

This study put Germany in the middle. Great Britain, New Zealand and Australia lead the asthma statistics; at the lower end of the scale are countries like Romania and Albania, with  Indonesia at the tailend with an asthma prevalence of under two percent.

Conclusion: The frequency of allergic diseases has been increasing steadily in the last 15 to 20 years, in 2010 every second Person will have an Allergy says the WHO.

What are the reasons for the increase?

The reasons for these frequent illnesses are not yet fully explored, concrete results can only be expected in the next few years. The following factors are suspected as possible causes:

- The change in our lives and habits
- Environmental influences, particularly diesel particulates.

A significant risk factor seems to be lifestyle and living style in Western industrial countries, because for example, eastern Germany has experienced a rapid increase in allergic diseases since the fall of the Berlin wall. Within just ten years, the low allergy rate in the East (despite the well-known local pollution!) has increased to the much higher Western level. Even a hereditary component is apparently existent.




Imprint:
Author: edited by Elke Gethmann
Created: 29.7.2004 revised 20.11.2008

Literature / guidelines / EBM:

Weißbuch Allergie in Deutschland 2004, Verlag Medizin und Wissen

The information may under no circumstances be considered a substitute for professional advice or treatment by a doctor. The contents of PureNature should not and may not be used to independently diagnose or begin treatment.