Effects of ambient temperature on atopic dermatitis and attributable health burden: a 6-year time-series study in Chengdu, China

Skin Physiological Parameters and Their Association with Severe Atopic Dermatitis in Mongolian Children

Background: Atopic dermatitis (AD) is a chronic skin condition that weakens the skin barrier, leading to increased trans-epidermal water loss and reduced skin moisture. Understanding how these changes in the skin barrier relate to AD severity in Mongolian children may offer insights that could apply to other regions facing similar environmental challenges. Methods: A cross-sectional study was conducted at the National Dermatology Center of Mongolia, involving 103 children with AD. Severity was assessed using the SCORAD index, and skin barrier function was measured through TEWL, skin moisture, and pH. Linear regression analyses were conducted, adjusting for age, skin physiological parameters, AD severity characteristics, and total IgE levels. Results: Among the participants, 48.54% were classified as having moderate AD, while 34.95% had severe AD. The mean SCORAD index was 43.19 ± 17.11. In the final adjusted regression analysis, higher TEWL was significantly associated with greater AD severity (non-lesional: B = 0.328, p = 0.004; lesional: B = 0.272, p = 0.007), while skin moisture showed an inverse association (non-lesional: B = -0.771, p < 0.001; lesional: B = -0.218, p < 0.001). The total IgE level was significantly higher in the severe AD group (p = 0.013). Although skin pH initially correlated with AD severity, it did not remain significant in multivariate analysis. Conclusions: This study emphasizes the role of skin barrier function, particularly increased TEWL and reduced moisture, in AD severity among Mongolian children.

Bathing in Atopic Dermatitis in Pediatric Age: Why, How and When

Atopic dermatitis is a chronic inflammatory skin disease. The treatment plays an important role in influencing the patients' quality of life. The basic management consists of appropriate skin cleansing, including bathing and eventually using bathing additives. Recommendations regarding frequency and duration of bathing, water temperature and usefulness of bathing additives are widely different, often leading to confusion among patients. This review aims to give insights into the best bathing practices and the use of bathing additives in atopic dermatitis in children. Several bathing additives, including bleach baths, commercial baby cleansers, bath baby oils and bath salt, appear to be promising adjunctive therapies for atopic dermatitis due to their anti-inflammatory, anti-bacterial, anti-pruritus and skin barrier repair properties through different mechanisms of action. However, their efficacy and safety are not fully understood in some cases. The usefulness of other bath additives, such as acidic and more natural substances (green tea extracts, pine tar, sodium bicarbonate), is still under investigation. Further studies are needed to determine their optimal use to achieve clinical benefit safely.

Physical influences on the skin barrier and pathogenesis of allergy

PURPOSE OF REVIEW

As the incidence of allergic conditions has increased in recent decades, the effects of climate change have been implicated. There is also increased knowledge on the effects of other physical influences, such as scratching and Staphylococcus aureus . The skin barrier is the first line of defense to the external environment, so understanding the ways that these factors influence skin barrier dysfunction is important.

RECENT FINDINGS

Although the impact on environmental exposures has been well studied in asthma and other allergic disorders, there is now more literature on the effects of temperature, air pollution, and detergents on the skin barrier. Factors that cause skin barrier dysfunction include extreme temperatures, air pollution (including greenhouse gases and particulate matter), wildfire smoke, pollen, scratching, S. aureus, and detergents.

SUMMARY

Understanding the ways that external insults affect the skin barrier is important to further understand the mechanisms in order to inform the medical community on treatment and prevention measures for atopic conditions.

The impact of temperature on the skin barrier and atopic dermatitis

Climate change is a global threat to public health and causes or worsens various diseases including atopic dermatitis (AD), allergic, infectious, cardiovascular diseases, physical injuries, and mental disorders. The incidence of allergy, such as AD, has increased over the past several decades, and environmental factors such as climate change have been implicated as a potential mechanism. A substantial amount of literature has been published on the impact of climate factors, including cold and hot temperatures, on the skin barrier and AD. Studies in several countries have found a greater incidence of AD in children born in the colder seasons of fall and winter. The effect of cold and warm temperatures on itch, skin flares, increased outpatient visits, skin barrier dysfunction, development of AD, and asthma exacerbations have been reported. Understanding mechanisms by which changes in temperature influence allergies is critical to the development of measures for the prevention and treatment of allergic disorders, such as AD and asthma. Low and high temperatures induce the production of proinflammatory cytokines and lipid mediators such as interleukin-1β, thymic stromal lymphopoietin, and prostaglandin E2, and cause itch and flares by activation of TRPVs such as TRPV1, TRPV3, and TRPV4. TRPV antagonists may attenuate temperature-mediated itch, skin barrier dysfunction, and exacerbation of AD.