We all know the many benefits of good skin care and moisturizer for people with atopic dermatitis/eczema, most importantly the ability to prevent eczema flare-ups. But today’s topic is how protecting your skin can also prevent asthma from happening! One thing most people know is that people with atopic dermatitis/eczema may themselves have allergic rhinitis or asthma, or a family member (related by blood) may have eczema, rhinitis or asthma. In layman’s terms, this means having “allergies”. But why do people with “allergies” get these diseases at the same time? What is the connection between these allergic diseases that occur in different organs? Most people don’t look into it, and in the academic world, it is still being researched and explored. In the academic world, we call the phenomenon of eczema or food allergy in infancy and rhinitis or asthma in school age the “allergy trilogy” or “allergic process”, which is the word march in English. As this diagram shows, for a part of the allergic children, it is possible that as they grow older, the allergic manifestations of different organs will appear step by step during their lifetime. So why is it that if you have eczema as a child, you are likely to develop asthma when you grow up? How are they connected when the skin is exposed and the lungs are hidden in the body? The answer is our immune system. Do not underestimate our skin, which is also an important immune organ of the body, and this organ is exposed from birth to feel various beneficial or harmful substances in the external environment. Most children who are prone to eczema are born with dry skin. Dry skin is like dry land with cracks on the surface that are invisible to the naked eye, so it is easier for many allergic substances from the outside world to enter the deeper layers of the skin and stimulate our immune system, thus creating an immune memory, which means that some cells in the body will remember these allergic substances and when you encounter the same allergic substances again (even if they are in other parts of the body), you will be able to remember them. When you encounter the same allergic substance again (even if it is in other parts of the body, such as the inhalation tract or intestines), the body’s immune system will attack it and produce an allergic reaction. Researchers have done an animal study in which the skin barrier of mice was artificially destroyed, and then the mice were given repeated exposure to ovalbumin (egg white) on the skin surface, and after a period of time, the ovalbumin was then dropped into the trachea of the mice, and the mice actually developed asthma! This animal study shows that when incomplete skin (eczema patients have dry skin with an incomplete skin barrier) is exposed to an allergen, the body may be sensitized, and asthma may occur after further exposure to the allergen. This is the academic community’s current understanding of the allergy development process “eczema → asthma”, so it is not alarming to say that protecting the skin to do a good job of moisturizing, repairing the skin barrier, and not allowing the skin to be repeatedly exposed to allergens sensitized, can prevent the occurrence of asthma!