Sweating is a normal physiological phenomenon of the skin. About 1.6-4 million exocrine sweat glands are located on the surface of the human skin and are responsible for the function of sweating, which is present at birth and is normal in full-term newborns. In our brain, there is a general command of sweating (hypothalamus sweating center), which senses temperature changes inside the body, and when the internal temperature of the body rises, it sends out instructions to regulate the sweating function of the exocrine sweat glands through sympathetic nerve production of acetylcholine, so sweating is an important way to regulate body temperature. Sweat does not only contain water, it is a sterile, dilute solution of electrolytes containing sodium chloride, potassium, bicarbonate, etc. It also contains antibacterial peptides (natural antibacterial substances produced by human skin), proteases, lactic acid, urea (natural moisturizing factor) and epidermal growth factor. Therefore sweating can also regulate the body’s water and electrolyte balance, increase the skin’s antibacterial ability, keep the skin’s stratum corneum moist, and keep the skin on the palms and feet soft. Sweating is so important to the normal function of the skin, but many eczema patients complain of itchy skin when they sweat. As we enter the hot and humid summer months, some eczema patients also experience an increase in eczema in the moist areas of the folds of the neck, elbow folds, popliteal folds and inner thighs. What should I do about this? Abnormal sweating function in eczema patients. Some eczema patients seldom sweat, even during strenuous exercise or hot summer days; some patients have itchy, red skin when they sweat; some patients have the most severe eczema in these folds of the neck, elbow folds and popliteal fossa, which do not heal over the years and get worse in summer. These are all signs of abnormal skin perspiration in eczema patients. It has been found that atopic dermatitis/eczema patients have reduced skin sweating function compared to healthy individuals, about half of normal, and that patients with atopic dermatitis/eczema have a longer response time to acetylcholine stimulation of sweating. This means that when people with eczema exercise or otherwise sweat through the skin to dissipate heat, it takes longer to do so and the amount of sweating is significantly less than normal. With less sweating, there is less water in the stratum corneum of the skin and the skin becomes dry and sensitive. Why does it itch after sweating? Since it is abnormal for eczema skin to sweat less, why does the skin itch more and even appear to worsen with eczema instead of sweating? The study found that there are several reasons: 1, when the need to sweat to dissipate heat, eczema skin is not able to produce a sufficient amount of sweat to help dissipate heat in a timely manner, it will cause the local skin temperature to rise, dryness aggravated, and therefore the feeling of itching. 2, a study found that eczema patients in the sweat of a protein, this protein comes from the skin surface colonization of spherical Malassezia (a fungus), can cause an allergic reaction to the skin (sweat allergic reaction), is also one of the reasons for the aggravation of eczema. 3, there are recent studies have found that the inflammatory substances produced in the inflammatory response of eczema skin, such as histamine, can further inhibit the sweating function and aggravate the itching symptoms when sweating. The pH of sweat is acidic when it is hidden (a small amount of sweat that you do not notice) and alkaline when it is visible to the naked eye. The alkaline pH of sweat in dominant sweating will cause skin irritation if it stays on the skin surface for a long time. What should I do if my eczema worsens after sweating? For the above reasons, we can develop countermeasures to relieve itchy skin and reduce the aggravation of eczema after sweating: 1, increase skin sweating through appropriate exercise, eczema skin needs more “moisturizing” sweat; 2, you can use some anti-malassezia drugs to reduce the colonization of Malassezia on the skin surface, reducing the sweat allergy; 3, after sweating The actual fact is that you will be able to get a lot more than just a couple of days to get a lot more than just a couple of days. How should eczema patients exercise? Eczema patients should not completely avoid sweating, because sweating can increase the moisture in the skin, increase the antibacterial ability of the skin, improve the dry skin condition. Exercise can promote skin perspiration, but many patients deliberately avoid exercise when their itchy skin worsens after exercise. It is recommended that when exercising, you choose the right exercise program according to the degree that your skin can tolerate after sweating, such as brisk walking, jogging, tai chi and other low-intensity exercise can be a good start, and then gradually increase the intensity of exercise as your skin tolerates the increase in sweating. Post-exercise skin care is also important: change wet clothes in time after sweating, shower and bath in time if possible, or prepare wet towels or mild wet wipes to wipe sweat in time, these measures can reduce the stimulation of sweat on the skin. The most important thing is that after rinsing or wiping sweat, you must apply moisturizer to the whole body or in the sweating area in time.