In a previous post, I introduced the topic of how the areas affected by atopic dermatitis change with age and their connection to sweating ability. Common areas for atopic dermatitis and why?

This diagram illustrates the basic structure of atopic dermatitis pathogenesis.

In reality, when you ask atopic dermatitis patients if they sweat, many report that they don't sweat much. They often say that they don't sweat much even when exercising or feeling hot. When touching or visually observing their skin, it's not only dry, but it also gives the impression that their sweat glands are somehow blocked.

Functions of Sweat and Skin Protection

As you well know, the primary function of sweat is thermoregulation. Additionally, the hydrolipidic film formed by a mixture of sebum and sweat covers the skin surface, acting as the skin's primary protective barrier (frontline barrier).

Sweat in the pathogenesis of atopic dermatitis — Source: Murota, H., et al. (2018). Allergology International. doi:10.1016/j.alit.2018.06.003

Various physiological components secreted with sweat also suppress microorganisms or are involved in anti-allergens. Furthermore, it plays a crucial role in skin barrier function, such as supplying adequate moisture to the skin. I primarily use the term 'conditioning' for this.

Complexity of the Sweat Excretion Process

This is a diagram illustrating sweat excretion and reabsorption. When I see diagrams like these, I generally understand that it's a very complex process and move on. However, the study mentioned above significantly notes that histamine-induced sweat excretion inhibition occurs during the sweat excretion process.

Reduced Sweat Excretion in Atopic Patients

In this regard, studies have confirmed that atopic patients, especially women, have a reduced ability to excrete sweat. In other words, atopic patients actually have a diminished capacity to excrete sweat, and the resulting impaired normal skin function could be a major factor increasing the likelihood of atopic dermatitis.

Relationship Between Sweat and Atopic Symptoms

It is also true that sweat has been identified as an aggravating factor for atopic dermatitis for a considerable time. This conclusion has been drawn multiple times in subjective survey studies conducted with patients. Most patients reported feeling that their symptoms worsened after sweating. Where did this discrepancy arise?

Recent studies suggest that we should distinguish between 'sweating' and 'sweat after sweating'. That is, the act of sweating itself helps activate skin function. However, the sweat secreted as a result of perspiration, if not wiped off quickly, can adversely affect skin conditioning, for example, by diluting skin pH.

Atopic Dermatitis Management Guidelines

Lifestyle guidance for atopic dermatitis — Source: Murota, H., & Katayama, I. (2016). Pediatric Allergy, Immunology, and Pulmonology. doi:10.1089/ped.2016.0723

Recent atopic dermatitis guidelines emphasize that while inducing sweating is beneficial, it must be followed by wiping off the sweat and adequately drying the skin. At this point, proper instruction on cleansing is, of course, necessary, because excessive cleansing is also not good.

When choosing underwear or undergarments, there is also a recommendation to opt for breathable materials like polyester rather than cotton, which absorbs sweat. This might be a useful tip.

Conclusion

In summary, a treatment strategy could be devised for atopic patients who do not sweat well, aiming to help them sweat effectively and thereby activate skin conditioning. This could involve using traditional Korean medicine, or introducing methods such as half-body baths or deep thermotherapy using high-frequency waves. While it varies by individual, in cases accompanied by dead skin cells and keratinization, mild exfoliation could even help promote sweat secretion.

In the next post, I will continue our discussion on moisturization.