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Increase in the number of allergic patients

Source of citation:"Current status of allergic diseases"(Health Department, Ministry of Health, Labor and Welfare)( on January 4, 2018)

The number of people who have allergies is increasing every year. According to an graph called “Annual trend of the estimated number of patients of allergies”, which published by the Health Bureau Ministry of Health, Labor and Welfare, they are in gradual increase trend. In this page, we introduce about the reasons of increasing of people who have allergies, which we think.

Hygiene hypothesis

Details are in the section of mechanism of type I allergy. There are two types of T cells,Th1 cells and Th2 cells. Th2 cells make IgE antibodies responsible for allergy. Normally, as people grow, Th1 cells grow through various infections. However, if people grow in an overly clean environment of modern society, the chance of infection is lost and Th1 cell growth is not done. As a result, Th2 cells remain stronger than Th1 cells. This is called hygiene hypothesis.

Increase of allergen and contact with the environment

It is also a fundamental problem that there are an increasing number of materials that can become allergens, such as an increase in mites and dust due to the improvement of living environments and structural changes of buildings and the appearance of air conditioners, and an increase in pollen due to the large amount of cedar trees planted. Once more, it is considered the cause that the chance contact with allergens is increasing. For example, increase intake of protein and animal fat due to changes in dietary habits.

Effect of exhaust gas

An increase in vehicles due to the development of society and an increase in exhaust gas in the atmosphere are considered to be one cause of developing allergy symptoms. In hay fever, exhaust gas is an bad factor that make the symptoms worth. As mentioned on the "Experiences about allergies" page, experiments with mice have shown that exhaust gas is related to hay fever.

Effect of stress

Excessive stress disturbs the autonomic nervous system and cortisol, an immune hormone, may not be secreted. One of cortisol’s functions is suppression of immune system, so if cortisol is not secreted, the immune function may be excessive and leading to allergic symptoms. Moreover, it is said that especially in allergic symptoms, atopic dermatitis and asthma are deeply related to stress.


The cause of the increase in the number of allergic patients in recent years is divided into two type, effects on allergens, such as an increase in allergen and an increase in contact with allergens, and influence on body functions like hygiene hypothesis and stress. Also, some of the cause can not be dealt with individually, such as vehicle exhaust gas and buildings. In order not to increase allergic patients anymore, it will be necessary to deal with the country.
It is very interesting that it affects not only eating habits and living environment, but also the child’s sanitary environment and the psychological state of the person. The casual part around us is the cause of onset. It will be a good chance to check yourself and surrounding environment once more.

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