ArticlePublisher preview available

Long‐term effect of azelaic acid peel on sebum production in acne

Wiley
Dermatologic Therapy
Authors:
To read the full-text of this research, you can request a copy directly from the authors.

Abstract and Figures

Background Seborrhea and the associated oily skin are undoubtedly the problem of women and men around the world. The pathogenesis of acne vulgaris involves excessive activity of sebaceous glands, as well as disturbances in the composition of sebum. Aims The aim of the study was to assess the severity of seborrhea in a group of acne vulgaris patients and to determine the effect of a 20% azelaic acid solution on the activity of sebaceous glands. Patients/Methods Twenty seven women, aged 19-25 years, underwent a series of six treatments with the application of a 20% solution of azelaic acid to the face. Results The mean values of sebum level showed a decreasing tendency. On the forehead, the results were as follows - 195.5 before the treatment and 162.7 two weeks after the last treatment. Measurements of the right cheek decreased from 175.3 to 141.3 The measurements taken three months after the study were 151. 3 on the forehead and 138. 9 on the cheek. Similarly, the values determining the total number of acne lesions and the severity of the disease according to the IGA scale also changed significantly. Conclusions Chemical peel with 20% azelaic acid shows long-term sebostatic action, which inhibits the formation of new acne lesions. This article is protected by copyright. All rights reserved.
This content is subject to copyright. Terms and conditions apply.
ORIGINAL ARTICLE
Long-term effect of azelaic acid peel on sebum production
in acne
Anna Szyma
nska
1
| Elzbieta Budzisz
1
| Anna Erkiert-Polguj
2
1
Department of Cosmetic Raw Materials
Chemistry, Faculty of Pharmacy, Medical
University of Lodz, Lodz, Poland
2
Department of Cosmetology and Aesthetic
Dermatology, Faculty of Pharmacy, Medical
University of Lodz, Lodz, Poland
Correspondence
Anna Erkiert-Polguj, Department of
Cosmetology and Aesthetic Dermatology,
Faculty of Pharmacy, Medical University of
Lodz, 90-151 Lodz, Muszynskiego Street
1, Poland.
Email: anna.erkiert-polguj@umed.lodz.pl
Abstract
Seborrhea and the associated oily skin are undoubtedly the problem of women and
men around the world. The pathogenesis of acne vulgaris involves excessive activity
of sebaceous glands, as well as disturbances in the composition of sebum. The aim of
the study was to assess the severity of seborrhea in a group of acne vulgaris patients
and to determine the effect of a 20% azelaic acid solution on the activity of seba-
ceous glands. Twenty seven women, aged 1925 years, underwent a series of six
treatments with the application of a 20% solution of azelaic acid to the face. The
mean values of sebum level showed a decreasing tendency. On the forehead, the
results were as follows195.5 before the treatment and 162.7 2 weeks after the last
treatment. Measurements of the right cheek decreased from 175.3 to 141.3 The
measurements taken 3 months after the study were 151.3 on the forehead and
138.9 on the cheek. Similarly, the values determining the total number of acne
lesions and the severity of the disease according to the IGA scale also changed signif-
icantly. Chemical peel with 20% azelaic acid shows long-term sebostatic action,
which inhibits the formation of new acne lesions.
KEYWORDS
acne, azelaic acid, peel, sebum
1|INTRODUCTION
Seborrhea and the associated oily skin are undoubtedly the problem
of thousands of women and men around the world, thus representing
a major challenge for modern medicine and cosmetology.
The sebaceous glands, also known as sebocytes, are an integral
part of the structure and function of the skin. The production of
sebum is crucial in maintaining skin homeostasis, the proper level of
its hydration and physiological defense against environmental and
infectious factors.
1,2
The number and size of sebocytes are not constant and vary
depending on the location. The highest density of sebaceous glands,
in relation to other areas of the body, can be observed on the face
(400900 sebocytes/cm
2
), on the scalp, as well as in the back and
chest area where they form the so-called seborrheic gutters.
2,3
The composition of sebum is also variable and differs, depending,
for example, on the species. The specific secretion of sebaceous glands
in humans consists mainly of triglycerides and free fatty acids, which
accounts for up to 57.5% of the sebum content. Additionally, other
components are, among others, wax esters, squalene, and cholesterol.
4
The function of sebaceous glands is directly controlled by the
endocrine system, particularly androgen hormones. They regulate the
activity of sebocytes by binding to nuclear androgen receptors (AR),
which in turn stimulates cell proliferation and lipogenesis.
1
The activ-
ity of the glands is also influenced by age, sex, and other factors, both
intrinsic (e.g., genetic predisposition) and extrinsic (e.g., environmental
factors, lifestyle, diet and care habits).
Abnormalities related to the function of sebaceous glands,
resulting in their excessive activity, as well as disturbances in the com-
position of sebum, can lead to the development of seborrhea or acne
vulgaris.
2
Received: 26 August 2021 Revised: 13 October 2021 Accepted: 1 November 2021
DOI: 10.1111/dth.15186
Dermatologic Therapy. 2022;35:e15186. wileyonlinelibrary.com/journal/dth © 2021 Wiley Periodicals LLC. 1of6
https://doi.org/10.1111/dth.15186
... This indicates that AZA peeling has a long-term inhibitory effect on sebaceous gland activity and improves acne treatment outcomes. 66 AZA can improve post-inflammatory erythema (PIE) and post-inflammatory hyperpigmentation(PIH). 67 A study evaluated the efficacy and safety of a 15% AZA gel in treating acne-induced PIE and PIH. A total of 72 patients with mild to moderate acne were enrolled and randomly assigned to two groups: the AZA group and the control group. ...
Article
Full-text available
AZA is a non-phenolic, saturated dicarboxylic acid with nine carbon atoms, naturally produced by the yeast Malassezia. It has diverse physiological activities, including antibacterial, anti-keratinizing, antimelanogenic, antioxidant and anti-inflammatory effects. AZA is widely used in dermatology and is FDA-approved for treating papulopustular rosacea. It also shows significant efficacy in acne vulgaris and melasma. This review summarizes the mechanisms of action and clinical applications of AZA, aiming to provide theoretical support for its clinical and cosmetic use and to facilitate further research.
... Badanie pozwoliło również zaobserwować, iż wyniki pomiarów sebumetrycznych wykonane po 3 miesiącach od zakończenia terapii były niższe niż wykonane po 2 tygodniach od jej zakończenia. W czasie analizy zaobserwowano również redukcję ilości zmian trądzikowych oraz stopnia nasilenia trądziku według skali IGA [21]. Wszystkie przytoczone badania dotyczące zastosowania kwasu azelainowego zarówno w terapii trądziku pospolitego, jak i przebarwień pozapalnych, wskazują na jego pozytywny wpływ i skuteczność oraz możliwość zastosowania w terapiach dotyczących tych problemów. ...
Article
Full-text available
Acne vulgaris is considered as one of the most common skin disorders. Its etiopathogenesis is based mainly on sebaceous gland overactivity, the influence of hormones, the presence of Cutibacterium acnes bacteria, abnormal keratinization of the outlets of the hair follicles and sebaceous glands, genetic factors and immunological disorders. Post-inflammatory hyperpigmentation occurs as a consequence of inflammatory skin conditions, such as acne vulgaris, and other similar diseases. They arise as a result of persistent inflammation, which stimulates melanocytes to synthesize melanin. The aim of this study was to evaluate the efficacy of 30% azelaic acid in a 25-year-old man with symptoms of acne vulgaris and post-inflammatory hyperpigmentation.
... More importantly, it can be used to treat inflammatory lesions in acne vulgaris. 16,17 TCA is used not only in anti-acne therapies but also in removing skin discolorations and acne scars. It is one of the strongest acids and has different side effects depending on the concentration used. ...
Article
Full-text available
Introduction: Acne vulgaris is a disease that has an enormous impact on appearance of the skin of the patients and also on their quality of life. Long-term dermatological treatment, which often lasts years, and disease relapses contribute to the occurrence of low self-esteem and depression. Acne is one of the 10 most common diseases in the world and the most common inflammatory skin disease. Many methods of dermatological treatment that bring very good results are available. However, educating people with acne on how to take care of their skin on a daily basis to minimize the bleak effects of the disease is an extremely important element. Contemporary cosmetology creates an environment for not only taking care of the skin at home, but also develops in-office treatments with exfoliation of the dead epidermis as an extremely important and priority part of treatment. The cosmetologist can propose both chemical and apparatus methods, which are selected individually for each client. Objective: The objective of this article is to provide information about cosmetological treatment used in acne vulgaris. Methods: In this article, we reviewed the published literature, article published in peer-reviewed journals. Results: There are many methods that work well in the case of acne skin care, more and more new treatments appear on the cosmetological market. Conclusion: Acne skin care in beauty parlor is very important element.
... 1 From a pathogenetic perspective, the development of facial acne might be influenced by the regulatory activity of sebaceous glands and disturbances in the sebum composition. 2 Subjects with even mild acne can show defective skin barrier, decreased skin hydration and increased sebum secretion. ...
Article
Full-text available
Background: Inflammatory and non-inflammatory acne lesions constitute a significant clinical challenge in acne subjects. Aim: To evaluate the efficacy and safety of a facial serum and a mask containing salicylic acid and lipohydroxy acid for improving skin conditions. Methods: This randomized controlled trial included adults with comedones, post-inflammatory erythema (PIE) and/or hyperpigmentation (PIH) in Shanghai, China in July 2021. Participants were randomly assigned 1:1 to receive the study Serum + Mask or serum alone for 8 weeks. Acne severity, comedones, papules, pustules, PIE, PIH, skin pores, skin tone evenness, sebum secretion, skin hydration, and trans-epidermal water loss were evaluated at T0d, T1d, T7d, T14d, T28d, and T56d. Results: Eighty-three participants were included, including 41 and 42 in the Serum + Mask and Serum groups, respectively. Acne severity, density of skin pores, skin tone evenness, PIH foci on face, PIE foci on nose, intensity of PIE and PIH, closed comedones on face, open comedones on nose, sebum secretion, and skin hydration were significantly improved from baseline after 8 weeks of treatment in both groups (all p < 0.05). Addition of the mask improved the number of closed comedones (-6.56 ± 0.39 vs. -5.19 ± 0.44, p = 0.022) and acne severity (-0.39 ± 0.08 vs. -0.12 ± 0.09, p = 0.026) substantially more than using the serum alone. No adverse reaction was reported in either group. Conclusions: The study serum improved skin conditions by regulating skin barrier function and achieving a balance of skin hydration and sebum secretion, removing comedones and improving PIE and PIH. Addition of the mask accelerated the effects without compromising safety.
... Ele tem a função de regular as glândulas sebáceas, propriedades queratolíticas, anti-inflamatórias e bacteriostáticas. (Szymańska et al., 2022). Ele é um ácido dicarboxílico que faz a inibição da síntese de proteína celular e normaliza o aumento da formação de grânulos de querato hialina no fundíbulo e diminui consideravelmente os comedões abertos e fechados. ...
Article
Full-text available
A patogênese da acne é um acometimento de alguns processos multifacetados dentro da unidade pilossebácea, dando espaço para o crescimento excessivo de bactérias e inflamação. Isso normalmente acontece no período da transição puberal, quando mudanças hormonais do corpo alteram a função da glândula pilossebácea, com isso, estudos mostraram que, em casos clínicos, o ácido azelaico é eficaz e seguro quando aplicado no local específico, onde se encontra a acne, e na concentração adequada. O objetivo deste estudo é identificar os benefícios do ácido azeláico no tratamento de acne vulgar em adolescentes, através de dados da literatura. Trata-se de uma revisão integrativa de literatura, que ela possibilita o resumo de vários estudos publicados, consentindo novos conhecimentos e resultados de outras pesquisas. A análise dos dados obtidos foi realizada após a organização dos artigos selecionados em um quadro contendo: autor, tema, objetivo, métodos, resultados, e ano de publicação. Pode-se concluir que o ácido azelaico tem um efeito positivo no tratamento da acne vulgar, quando aplicado da forma correta, quantidade ideal e de forma pontual. É de grande importância um acompanhamento com um profissional, pois o ácido, apesar de promover efeitos colaterais toleráveis, pode causar disfunções maiores caso não seja analisado o tipo de acne, a pele ou o estilo de vida do adolescente.
Article
Full-text available
Introdução: A acne vulgar é uma doença inflamatória crônica de caráter tópico, que pode ocasionar lesões em tipo de comedões, pápulas, pústulas, nódulos, cistos, e mais gravemente podem gerar cicatrizes em graus variáveis. Apresenta patogênese multifatorial, que podem causar aparência inestética e consequências psicossociais. Entretanto, existem diversas modalidades terapêuticas para o tratamento da acne vulgar, desde terapias farmacológicas e estéticas que auxiliam na melhora da aparência da pele acometida, dentre eles, destaca-se o peeling químico. Objetivo: Reunir e analisar evidências sobre a utilização dos peelings químicos no tratamento da acne vulgar, através de um estudo de revisão integrativa da literatura. Material e Métodos: Para a realização da pesquisa foram utilizadas as bases de dados PubMed e a Biblioteca Virtual em Saúde (BVS), buscando publicações no idioma inglês, português e espanhol, publicados nos últimos 10 anos. Com relação a seleção dos estudos, foi realizada segundo critérios de inclusão e exclusão estabelecidos nesta revisão, ao final, 23 publicações foram selecionadas para análise crítica. Resultados: Os peelings químicos mais utilizados foram os muitos superficiais e superficiais, dentre eles, o mais predominante foi o peeling de ácido salicílico. Já com relação aos peelings combinados, os mesmos apresentaram menores efeitos colaterais, além disso, o uso concomitante do peeling químico juntamente com outra terapia demonstrou ser eficaz, obtendo bons resultados. Conclusão: Como evidenciado nos estudos selecionados, observou-se redução das lesões da acne e melhora no aspecto geral da pele, refletindo diretamente na satisfação dos pacientes, bem como na melhoria da qualidade de vida, demonstrando ser uma opção de tratamento efetivo e seguro.
Article
Full-text available
Purpose Numerous tools are available to assess acne severity. It is important to have an acceptable and easy to use tool for acne assessment for many reasons, such as initial assessment and follow-ups, clinical trials, and comparisons of clinical studies. The aim was to investigate the agreement between different observers (inter-observer variation) in the evaluation using the Global Acne Grading System (GAGS) and Investigator Global Assessment of Acne (IGA). Besides, to investigate the correlation between the assessment scores and its relation to the quality of life scales Dermatology Life Quality Index (DLQI) and the Cardiff Acne Disability Index (CADI). Patients and Methods This was a prospective study. Four investigators involved to evaluate the study subject surveyed 54 patients complaining of acne using IGA and GAGS scores (DLQI and CADI). Results A significant relation was seen between GAGS and IGA (Pearson chi-square test p= 0.001), and they demonstrated excellent inter-rater reliability. There was no correlation between IGA and quality of life measures (CADI nor DLQI). However, there was a significant weak correlation between GAGS and CADI. Conclusion The two methods for acne severity assessment are reliable, and they are correlated. Quality of life concerning acne is not correlated with the severity of the disease.
Article
Full-text available
Acne is a kind of chronic inflammatory skin disease, which is common in the hair follicle and sebaceous gland of teenagers. It often recurs and affects the quality of life of patients. Acne itself can cause the damage of skin barrier function. On the other hand, common acne treatment methods, such as external drugs, systemic drugs, physical and chemical treatment, can also lead to the damage of skin barrier function and affect the treatment effect. The application of skin care in the adjuvant treatment of acne has been widely concerned. Due to their high safety, good tolerance and the effect of improve the damaged skin barrier, medical skin care products are a hot spot in the treatment of cosmetic skin diseases in recent years. It can not only increase the curative effect, reduce the side effectsbut alsoincrease the compliance of patients when combined with conventional acne treatment. In this paper, skin care products and their application in acne treatment were reviewed. This article is protected by copyright. All rights reserved.
Article
Full-text available
This review focuses on the treatment options for adult female patients with acne. Acne in adult female patients may start during adolescence and persist or have an onset in adulthood. Acne has various psychosocial effects that impact patients' quality of life. Treatment of acne in adult women specifically has its challenges due to the considerations of patient preferences, pregnancy, and lactation. Treatments vary widely and treatment should be tailored specifically for each individual woman. We review conventional therapies with high levels of evidence, additional treatments with support from cohort studies and case reports, complementary and/or alternative therapies, and new agents under development for the treatment of patients with acne.
Article
Full-text available
The major role of sebaceous glands in mammals is to produce sebum, which coats the epidermis and the hair providing waterproofing, thermoregulation and photoprotection. However, as the need for these functions decreased along the evolutionary changes in humans, a relevant question has been raised: are sebaceous glands and sebum the remnants of our mammalian heritage or do they have overtaken a far more complex role in human skin biology? Trying to provide answers to this question, this review introduces the evolving field of sebaceous immunobiology and puts into the focus the pathways that sebum lipids use to influence the immune milieu of the skin. By introducing possible modifiers of sebaceous lipogenesis and discussing the – human-specific – alterations in composition and amount of sebum, the attribute of sebum as a sensitive tool, which is capable of translating multiple signalling pathways into the dermal microenvironment is presented. Further their interaction with macrophages and keratinocytes involves sebum lipid fractions into disease pathogenesis, which could lead – on the other side – to the development of novel sebum-based therapeutic strategies.
Article
Full-text available
The skin microbiome varies across individuals. The causes of these variations are inadequately understood. We tested the hypothesis that inter-individual variation in facial skin microbiome can be significantly explained by variation in sebum and hydration levels in specific facial regions of humans. We measured sebum and hydration from forehead and cheek regions of healthy female volunteers (n = 30). Metagenomic DNA from skin swabs were sequenced for V3-V5 regions of 16S rRNA gene. Altogether, 34 phyla were identified; predominantly Actinobacteria (66.3%), Firmicutes (17.7%), Proteobacteria (13.1%) and Bacteroidetes (1.4%). About 1000 genera were identified; predominantly Propionibacterium (58.6%), Staphylococcus (8.6%), Streptococcus (4.0%), Corynebacterium (3.6%) and Paracoccus (3.3%). A subset (n = 24) of individuals were sampled two months later. Stepwise multiple regression analysis showed that cheek sebum level was the most significant predictor of microbiome composition and diversity followed by forehead hydration level; forehead sebum and cheek hydration levels were not. With increase in cheek sebum, the prevalence of Actinobacteria (p = 0.001)/Propionibacterium (p = 0.002) increased, whereas microbiome diversity decreased (Shannon Index, p = 0.032); this was opposite for other phyla/genera. These trends were reversed for forehead hydration levels. Therefore, the nature and diversity of facial skin microbiome is jointly determined by site-specific lipid and water levels in the stratum corneum.
Article
Full-text available
Acne is a multifactorial skin disorder frequently observed during adolescence with different grades of severity. Multiple factors centering on sebum secretion are implicated in acne pathogenesis. Despite the recognized role of sebum, its compositional complexity and limited analytical approaches have hampered investigation of alterations specifically associated with acne. To examine the profiles of lipids distribution in acne sebum, 61 adolescents (29 males and 32 females) were enrolled in this study. Seventeen subjects presented no apparent clinical signs of acne. The 44 affected individuals were clinically classified as mild (13), moderate (19), and severe (12) acne. Sebum was sampled from the forehead with SebutapeTM adhesive patches. Profiles of neutral lipids were acquired with RR-RP/HPLC-TOF/MS in positive ion mode. Univariate and multivariate statistical analyses led to the identification of lipid species with significantly different levels between healthy and acne sebum. The majority of differentiating lipid species were diacylglycerols, followed by fatty acyls, sterols, and prenols. Overall, the data indicated an association between the clinical grading of acne and sebaceous lipid fingerprints and highlighted diacylglycerols as more abundant in sebum from adolescents affected with acne.
Article
Background: Acne is a common, chronic, inflammatory disease of the pilosebaceous unit. It has a significant impact on patient quality of life, especially when lesions occur on cosmetically sensitive areas. Chemical peeling is a well-known option in the treatment of acne vulgaris, but little is known about azelaic acid (AZA) peels. Objectives: To determine the efficacy of 30% AZA peel, in decreasing the amount of secreted sebum, and reducing acne lesions. Methods: The study involved 35 women, with acne lesions on face skin. All the subjects underwent a series of six treatments, performed every 2 weeks. Results: A series of treatments contributed to a statistically significant reduction in the amount of secreted sebum. Similarly, highly significant values determining the overall number of acne lesions and the severity of the disease according to the IGA scale were also changed. The procedure was well tolerated by all participants. Conclusions: Peels with 30% AZA reduced acne lesions and normalized the activity of the sebaceous glands. The reduction of sebum allows us to believe that obtained good results in patients will be stable and long-lasting.
Article
Background: Azelaic acid demonstrates anti-inflammatory, anti-oxidative, anti-comedogenic, and anti-microbial effects. Azelaic acid 20% cream is currently approved for the treatment of acne vulgaris, and azelaic acid 15% foam has recently been approved for rosacea. Given the favorable tolerability profile of foam preparations, it is reasonable to assume that azelaic acid 15% foam could serve as a viable treatment option for facial acne. Objective: To examine the efficacy and safety of azelaic acid 15% foam in the treatment of moderate-to-severe facial acne Methods: Twenty subjects with moderate-to-severe facial acne vulgaris were enrolled in this two-center, open-label pilot study. All study subjects were treated with azelaic acid 15% foam for 16 weeks. Efficacy analyses were based on the change in facial investigator global assessment (FIGA) and changes in total, inflammatory, non-inflammatory lesion counts between baseline and week 16. Results: There was a significant reduction in FIGA scores from baseline to week 16 (p = .0004), with 84% of subjects experiencing at least a 1 grade improvement, and 63% of subjects achieving a final grade of Clear or Almost Clear. All subjects experienced reductions in inflammatory and total lesion counts by week 16, and 89% of subjects experienced reductions in non-inflammatory lesions. Azelaic acid 15% foam was well tolerated, with almost all instances of erythema, dryness, peeling, oiliness, pruritus, and burning being of mild or trace degree, and most adverse effects resolving by the end of the study. Conclusion: Azelaic acid 15% foam is effective and safe in the treatment of facial acne vulgaris. Given the convenience of foam vehicles, azelaic acid 15% foam should be considered as a viable treatment option for this condition. J Drugs Dermatol. 2018;17(6):641-645.
Article
Alterations of skin surface lipid (SSL) are believed to be one important factor of acne pathogenesis and SSL plays a key role in the initiation of the acne lesions. In this study, a powerful analytical technique, UPLC‐QTOF‐MS, was used to investigate the SSL variations of lipid main classes, subclasses and individual species. A total of 70 subjects (35 acne patients and 35 controls) were selected for this study. Multivariate data analysis showed significant differences between two groups. Significant increased levels of 3 main classes of glycerophospholipids, fatty acyls, and sterol lipids and significant decreased levels of 2 main classes of prenol lipids and saccharolipids were monitored in acne patients. Subsequent analysis showed that there were 18 subclasses significantly varied and shared the same changing trends of their belonging main classes. Multivariate data analysis indicated that 36 entities were the most important individual species responsible for the discrimination and phosphatidylserines were the majority of differentiating lipid species. In addition, the reduction of ceramides chain length and increase in unsaturated free fatty acids, contributed to an altered lipid organization and decreased skin barrier function in acne patients. This article is protected by copyright. All rights reserved.
Article
Objective: The epidermis is an epidermal barrier which accumulates lipid substances and participates in skin moisturizing. An evaluation of the epidermal barrier efficiency can be made, among others, by the measurement of the following values: the lipid coat, the transepidermal water loss (TEWL) index, and pH. Materials: The study involved 50 Caucasian, healthy women aged 19-35 years (mean 20.56). Methods: Measurements were made using Courage & Khazaka Multi Probe Adapter MPA 580: Tewameter TM 300, pH-Meter PH 905, Sebumeter SM 815. The areas of measurements included forehead, nose, left cheek, right cheek, chin, and thigh. Results: In the T-zone, the lipid coat was in the range between 0 and 270 μg/cm(2) (mean 128 μg/cm(2) ), TEWL between 1 and 55 g/m(2) /h (mean 11.1 g/m(2) /h), and pH 4.0-5.6 (mean 5.39). Lower values of the lipid coat up to 100 μg/cm(2) were accompanied by TEWL greater than 30 g/m(2) /h and less acidic pH of 5.6-9.0. In the U-zone the range of lipid coat was up to 200 μg/cm(2) (mean 65.2 μg/cm(2) ), the skin pH remained 4.0-5.6 (mean 5.47), and TEWL was in the range between 1 and 20 g/m(2) /h (mean 8.7 g/m(2) /h). Lower values of the lipid coat up to 100 μg/cm(2) were accompanied by TEWL between 1 and 20 g/m(2) /h and less acidic pH of 5.6-9.0. High values of the lipid coat between 180 and 200 μg/cm(2) were connected with TEWL of 1-15 g/m(2) /h. On the skin of the thigh, we observed a very thin lipid coat - 35 μg/cm(2) (mean 5.6 μg/cm(2) ), pH (mean 5.37), and TEWL (mean 8.5 g/m(2) /h) were considered by us to be within regular limits. Conclusions: In the T-zone, a thinner lipid coat resulted in relatively high TEWL and pH levels changing toward alkaline. In the U-zone, thinner lipid coat was accompanied by lower TEWL and pH changing toward alkaline. We also observed that lower values of lipid coat up to 100 μg/cm(2) were associated with higher pH values ranging toward the basic character pH 5.6-9.0).