What causes Allergies?

March 07 00:27 2019 Print This Article

It includes the two categories mainly the host and environmental factors. The host factors include the sex, hereditary, race and age. Out of all this the most important factor is hereditary. The incidence of the allergic diseases has increased recently and this has been due to the involvement of multiple factors. There are 4 main environmental reasons which include the exposure to infections, they occur in the early childhood and environmental pollution, allergen levels and dietary changes.

1. The genetic basis includes the familial identical twins which are likely to have a same familiar disease 70 percent of the time. The chances of occurring the same allergy are 40 percent in case of non identical twins. The allergic patients are more likely to have allergic children’s. Their allergies are likely to be more severe and are not consistent with the genealogies in which the patients are allergic to pea nuts. They may have children which are allergic to the ragweed. The chances of developing the allergy are inherited and are caused due to the irregularity in immune system but there is no specific allergen. The risk of allergic sensitization varies with the age with young children more at risk as compared to the old people.

The levels of IgE are highest in the childhood time and lowest in the age between 10 to 30 years. The prevalence of hay fever is highest in case of children and young adults. The incidence of asthma is highest in the children which are less than 10 years of age. The boys have a more risk of developing an allergy as compared with the girls. But in the case of asthma the condition is vice a versa. In the adult hood the sex differences are likely to reduce and ethnicity play a vital role in the study of allergens. The racial factors cannot be differentiated from the environmental factors and they change due to the migration. There are different genetic loci which lead to asthma mainly the people of Europe, Hispanic, Asian and African origin.

2. Hygiene hypothesis includes the allergic diseases which are caused by the inappropriate immunological response to harmless antigens which are driven by the TH 2 mediated immune response. It was proposed by the D P Strachan. There are many bacteria and viruses which can lead to the TH 1 mediated immune response. It down regulates the TH 2 response. The first mechanism of the action of hygiene hypothesis is that the insufficient stimulation of the TH1 arm of immune system may lead to the over active TH 2 arm. It leads to allergic reactions. One can also say that the individuals which reside in the sterile environment are not exposed to the pathogens so that their immune system can be kept busy. Our bodies have evolved to deal with a certain level of pathogens when it is not exposed to the level of immune system which will attack harmless antigens.

They include the normal benign objects like pollen which will trigger an immune response. The hypothesis was developing to explain the observations that the hay fever and eczema are allergic diseases. They are not common in the children with large families. They were exposed to more infectious agents than the siblings and other children from the family with a single child. This hypothesis has been investigated widely by an epidemiologists and immunologists. It has become an important network for the study of allergic disorders. It also explains the increase in allergic diseases since the age of industrialization. There is a higher incidence of allergic diseases in the developed countries. The hypothesis also explains the exposure to symbiotic bacteria and parasites as important modulator of immune system development with infectious agents. There is an epidemiological data which shows that this hypothesis is supported.

There are few studies which have shown that the various immunological and epidemiological diseases are not so common in the developing country as compared to the developed country. There are immunological disorders as a country grows affluent and cleaner. The use of antibiotic in the first year of life has been linked to asthma and other disorders. As the usage of anti bacterial cleaning products has increased there has been link with a higher incidence of asthma and it has birth by the cesarean section and not vaginal.

3. The environmental factors include the international differences that have been associated with the number of individuals within a population that suffer from the allergy. These disorders are common in the developed country as compared to the developing countries and are less common in the traditional countries. The rate also differs in the urban as well as rural population. These differences are not well defined. The risk factor for allergy is the exposure to allergens. The change in exposure to micro organisms is other important feature of the explanation of increase in the atopic allergy.

The exposure to endo toxin decreases the release of inflammatory cytokines like TNF ALPHA and IFN gamma. There is also a release of inter leukin 10 and 12 from white blood cells which are referred as leucocytes. They circulate in the blood. There are certain proteins known as the microbe sensing. These are also known as the toll like receptors. They are found on the surface of cells in the body and are believed to be involved in these processes. There are gut worms and similar parasites which are present in the un treated drinking water and can lead to the allergies. They can be present in the developing as well as developed countries. They are eliminated by the process of chlorination and purification.

There are certain parasites like the intestinal worms which have the ability to secrete in the gut wall and suppress the immune system. They prevent the body from attacking the parasite. They include the hook worm. They gave rise to the co evolution of man and parasites. They form an immune system that functions correctly in the presence of parasites. If they are not present the immune system becomes depressed and unbalanced. There are few studies which suggest that the allergies are in relation with the delayed establishment of gut flora in the infants. But the results are not supporting and there are some studies which have been done in the china and Ethiopia and have shown that there is increase in the allergy in the people which are infected with intestinal worms. There are clinical trials which have been done to know the effectiveness of few worms in treating this disorder. The term parasite is not correct and it leads to the unknown symbiosis at work.

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