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Stratum corneum hydration and skin surface pH in patients with atopic dermatitis
Tanja Knor1, Ajša Meholjić-Fetahović, Aida Mehmedagić
1University Department of Dermatovenereology, Sarajevo University Clinical Center, Bosnia and Herzegovina. knor@bih.net.ba
Insights
Atopic dermatitis (AD) is linked to a weakened skin barrier. This study found reduced skin hydration and increased pH in AD patients, even in uninvolved skin, indicating impaired barrier function.
Area of Science:
- Dermatology
- Biophysics
- Skin Physiology
Background:
- Atopic dermatitis (AD) is a chronic skin condition often starting in childhood.
- Skin barrier dysfunction, characterized by dryness and itching, is a hallmark of AD.
- Measuring stratum corneum hydration and skin surface pH are noninvasive methods to assess skin barrier function.
Purpose of the Study:
- To evaluate skin barrier function in atopic dermatitis patients.
- To compare stratum corneum hydration and skin surface pH in lesional, perilesional, and uninvolved skin of AD patients versus healthy controls.
Main Methods:
- Utilized Courage AND Khazaka combined units (SM810/CM820/pH900) for measurements.
- Assessed water capacitance (hydration) and skin surface pH on the forearm.
- Included 21 AD patients (young and adult) and 21 age-matched healthy controls.
Main Results:
- AD patients showed significantly decreased water capacitance (44.1 AU on lesions) and increased skin pH (6.13 on lesions) compared to controls (74.1 AU, 5.24 pH).
- Impaired barrier function (lower capacitance, higher pH) was observed in lesional, perilesional, and even uninvolved skin of AD patients.
- Uninvolved skin in AD patients exhibited significantly worse barrier function parameters than in healthy controls.
Conclusions:
- Skin barrier function is demonstrably degraded in atopic dermatitis patients.
- This degradation is particularly evident in lesional skin but also affects uninvolved skin.
- Findings highlight the systemic nature of skin barrier impairment in AD.
Abstract:
Atopic dermatitis (AD) is a chronically relapsing skin disease with genetic predisposition, which occurs most frequently in preschool children. It is considered that dryness and pruritus, which are always present in AD, are in correlation with degradation of the skin barrier function. Measurement of hydration and pH value of the stratum corneum is one of the noninvasive methods for evaluation of skin barrier function. The aim of the study was to assess skin barrier function by measuring stratum corneum hydration and skin surface pH of the skin with lesions, perilesional skin and uninvolved skin in AD patients, and skin in a healthy control group. Forty-two patients were included in the study: 21 young and adult AD patients and 21 age-matched healthy controls. Capacitance, which is correlated with hydration of stratum corneum and skin surface pH were measured on the forearm in the above areas by SM810/CM820/pH900 combined units (Courage AND Khazaka, Germany). The mean value of water capacitance measured in AD patients was 44.1 ± 11.6 AU (arbitrary units) on the lesions, 60.2 ± 12.4 AU on perilesional skin and 67.2 ± 8.8 AU on uninvolved skin. In healthy controls, the mean value was 74.1 ± 9.2 AU. The mean pH value measured in AD patients was 6.13 ± 0.52 on the lesions, 5.80 ± 0.41 on perilesional skin, and 5.54 ± 0.49 on uninvolved skin. In control group, the mean pH of the skin surface was 5.24 ± 0.40. The values of both parameters measured on lesional skin were significantly different (capacitance decreased and pH increased) from the values recorded on perilesional skin and uninvolved skin. The same held for the relation between perilesional and uninvolved skin. According to study results, the uninvolved skin of AD patients had significantly worse values of the measured parameters as compared with control group. The results of this study suggested the skin barrier function to be degraded in AD patients, which is specifically expressed in lesional skin.
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