Peer-reviewed

References

Academic references supporting The Damaged Skin Barrier, organised by chapter.

This page brings together the research behind the book’s explanations of barrier damage, repair, irritation, inflammation, pH, lipids, skin biology and more.

Organised by Chapter

Chapter 1

Baumann, L. (2008).
Understanding and treating various skin types: the Baumann Skin Type Indicator.
Dermatologic Clinics, 26(3), pp. 359–373, vi.
https://doi.org/10.1016/j.det.2008.03.007

Blank, I.H. (1952).
Factors which influence the water content of the stratum corneum.
Journal of Investigative Dermatology, 18(6), pp. 433–440.
https://doi.org/10.1038/jid.1952.52

Bouwstra, J.A. and Ponec, M. (2006).
The skin barrier in healthy and diseased state.
Biochimica et Biophysica Acta – Biomembranes, 1758(12), pp. 2080–2095.
https://doi.org/10.1016/j.bbamem.2006.06.021

Cork, M.J., Danby, S.G., Vasilopoulos, Y., et al. (2009).
Epidermal barrier dysfunction in atopic dermatitis.
Journal of Investigative Dermatology, 129(8), pp. 1892–1908.
https://doi.org/10.1038/jid.2009.133

Del Rosso, J.Q., Zeichner, J., Alexis, A., et al. (2016).
Understanding the epidermal barrier in healthy and compromised skin: clinically relevant information for the dermatology practitioner.
Journal of Clinical and Aesthetic Dermatology, 9(4 Suppl 1), pp. S2–S8.
No DOI available.

Elias, P.M. (1983).
Epidermal lipids, barrier function, and desquamation.
Journal of Investigative Dermatology, 80(1 Suppl), pp. 44s–49s.
https://doi.org/10.1038/jid.1983.12

Feingold, K.R. (2007).
The role of epidermal lipids in cutaneous permeability barrier homeostasis.
Journal of Lipid Research, 48(12), pp. 2531–2546.
https://doi.org/10.1194/jlr.R700013-JLR200

Fluhr, J.W. and Elias, P.M. (2002).
Stratum corneum pH: formation and function of the ‘acid mantle’.
Exogenous Dermatology, 1(4), pp. 163–175.
https://doi.org/10.1159/000066140

Hachem, J.-P., Crumrine, D., Fluhr, J., et al. (2003).
pH directly regulates epidermal permeability barrier homeostasis, and stratum corneum integrity/cohesion.
Journal of Investigative Dermatology, 121(2), pp. 345–353.
https://doi.org/10.1046/j.1523-1747.2003.12365.x

Madison, K.C. (2003).
Barrier function of the skin: “la raison d’être” of the epidermis.
Journal of Investigative Dermatology, 121(2), pp. 231–241.
https://doi.org/10.1046/j.1523-1747.2003.12359.x

Nemes, Z. and Steinert, P.M. (1999).
Bricks and mortar of the epidermal barrier.
Experimental & Molecular Medicine, 31(1), pp. 5–19.
https://doi.org/10.1038/emm.1999.2

Proksch, E., Brandner, J.M. and Jensen, J.-M. (2008).
The skin: an indispensable barrier.
Experimental Dermatology, 17(12), pp. 1063–1072.
https://doi.org/10.1111/j.1600-0625.2008.00786.x

Tupker, R.A., Pinnagoda, J. and Nater, J.P. (1990).
The transient and cumulative effect of sodium lauryl sulphate on the epidermal barrier assessed by transepidermal water loss: inter-individual variation.
Acta Dermato-Venereologica, 70(1), pp. 1–5.
https://doi.org/10.2340/000155557015

Chapter 2

Behne, M.J., Sanchez, S., Barry, N.P., et al. (2011).
Major translocation of calcium upon epidermal barrier insult: imaging and quantification via FLIM/Fourier vector analysis.
Archives of Dermatological Research, 303(2), pp. 103–115.
https://doi.org/10.1007/s00403-010-1113-9

Boer, D.E.C., van Smeden, J., Al-Khakany, H., et al. (2020).
Skin of atopic dermatitis patients shows disturbed β-glucocerebrosidase and acid sphingomyelinase activity that relates to changes in stratum corneum lipid composition.
Biochimica et Biophysica Acta – Molecular and Cell Biology of Lipids, 1865(6), 158673.
https://doi.org/10.1016/j.bbalip.2020.158673

Elias, P.M. (1983).
Epidermal lipids, barrier function, and desquamation.
Journal of Investigative Dermatology, 80(1 Suppl), pp. 44s–49s.
https://doi.org/10.1038/jid.1983.12

Elias, P.M., Brown, B.E., Crumrine, D., et al. (2002).
Origin of the epidermal calcium gradient: regulation by barrier status and role of active vs passive mechanisms.
Journal of Investigative Dermatology, 119(6), pp. 1269–1274.
https://doi.org/10.1046/j.1523-1747.2002.19622.x

Feingold, K.R. (2007).
The role of epidermal lipids in cutaneous permeability barrier homeostasis.
Journal of Lipid Research, 48(12), pp. 2531–2546.
https://doi.org/10.1194/jlr.R700013-JLR200

Feingold, K.R. (2009).
The outer frontier: the importance of lipid metabolism in the skin.
Journal of Lipid Research, 50(Suppl), pp. S417–S422.
https://doi.org/10.1194/jlr.R800039-JLR200

Groen, D., Gooris, G.S. and Bouwstra, J.A. (2009).
New insights into the stratum corneum lipid organization by small-angle X-ray diffraction.
Biophysical Journal, 97(8), pp. 2242–2249.
https://doi.org/10.1016/j.bpj.2009.07.040

Groen, D., Poole, D.S., Gooris, G.S., et al. (2011).
Is an orthorhombic lateral packing and a proper lamellar organization important for the skin barrier function?
Biochimica et Biophysica Acta – Biomembranes, 1808(6), pp. 1529–1537.
https://doi.org/10.1016/j.bbamem.2010.10.015

Hachem, J.-P., Roelandt, T., Schürer, N., et al. (2010).
Acute acidification of stratum corneum membrane domains using polyhydroxyl acids improves lipid processing and inhibits degradation of corneodesmosomes.
Journal of Investigative Dermatology, 130(2), pp. 500–510.
https://doi.org/10.1038/jid.2009.249

Hamanaka, S., Hara, M., Nishio, H., et al. (2002).
Human epidermal glucosylceramides are major precursors of stratum corneum ceramides.
Journal of Investigative Dermatology, 119(2), pp. 416–423.
https://doi.org/10.1046/j.1523-1747.2002.01836.x

Hennings, H., Michael, D., Cheng, C., et al. (1980).
Calcium regulation of growth and differentiation of mouse epidermal cells in culture.
Cell, 19(1), pp. 245–254.
https://doi.org/10.1016/0092-8674(80)90406-7

Hill, J.R., Paslin, D. and Wertz, P.W. (2006).
A new covalently bound ceramide from human stratum corneum –ω- hydroxyacylphytosphingosine.
International Journal of Cosmetic Science, 28(3), pp. 225–230.
https://doi.org/10.1111/j.1467-2494.2006.00324.x

Holleran, W.M., Ginns, E.I., Menon, G.K., et al. (1994).
Consequences of β-glucocerebrosidase deficiency in murine epidermis: abnormal stratum corneum structure and permeability barrier.
Journal of Clinical Investigation, 93(4), pp. 1756–1764.
https://doi.org/10.1172/JCI117160

Howell, M.D., Kim, B.E., Gao, P., et al. (2007).
Cytokine modulation of atopic dermatitis filaggrin skin expression.
Journal of Allergy and Clinical Immunology, 120(1), pp. 150–155.
https://doi.org/10.1016/j.jaci.2007.04.031

Jančálková, P., Kopečná, M., Kurka, M., et al. (2023).
Skin barrier fine-tuning through low-temperature lipid chain transition.
Journal of Investigative Dermatology, 143(12), pp. 2427–2435.e3.
https://doi.org/10.1016/j.jid.2023.06.193

Janssens, M., van Smeden, J., Gooris, G.S., et al. (2012).
Increase in short-chain ceramides correlates with an altered lipid organization and decreased barrier function in atopic eczema patients.
Journal of Lipid Research, 53(12), pp. 2755–2766.
https://doi.org/10.1194/jlr.P030338

Lee, S.H., Elias, P.M., Proksch, E., et al. (1992).
Calcium and potassium are important regulators of barrier homeostasis in murine epidermis.
Journal of Clinical Investigation, 89(2), pp. 530–538.
https://doi.org/10.1172/JCI115617

Leprince, C. and Simon, M. (2025).
Epidermal lamellar bodies, essential organelles for the skin barrier.
Frontiers in Cell and Developmental Biology, 13, 1597884.
https://doi.org/10.3389/fcell.2025.1597884

Mahanty, S. and Setty, S.R.G. (2021).
Epidermal lamellar body biogenesis: insight into the roles of Golgi and lysosomes.
Frontiers in Cell and Developmental Biology, 9, 701950.
https://doi.org/10.3389/fcell.2021.701950

Menon, G.K., Price, L.F., Bommannan, B., et al. (1994).
Selective obliteration of the epidermal calcium gradient leads to enhanced lamellar body secretion.
Journal of Investigative Dermatology, 102(5), pp. 789–795.
https://doi.org/10.1111/1523-1747.ep12377921

Menon, G.K. (2018).
An overview of epidermal lamellar bodies: novel roles in biological adaptations and secondary barriers.
Journal of Dermatological Science, 92(1), pp. 10–17.
https://doi.org/10.1016/j.jdermsci.2018.03.005

Nemes, Z. and Steinert, P.M. (1999).
Bricks and mortar of the epidermal barrier.
Experimental & Molecular Medicine, 31(1), pp. 5–19.
https://doi.org/10.1038/emm.1999.2

Norlén, L., Plasencia, I. and Bagatolli, L. (2008).
Stratum corneum lipid organization as observed by atomic force, confocal and two-photon excitation fluorescence microscopy.
International Journal of Cosmetic Science, 30(6), pp. 391–411.
https://doi.org/10.1111/j.1468-2494.2008.00458.x

Opálka, L., Kováčik, A., Pullmannová, P., et al. (2020).
Effects of omega-O-acylceramide structures and concentrations in healthy and diseased skin barrier lipid membrane models.
Journal of Lipid Research, 61(2), pp. 219–228.
https://doi.org/10.1194/jlr.RA119000420

Opálka, L., Meyer, J.M., Ondrejčeková, V., et al. (2022).
ω-O-Acylceramides but not ω-hydroxy ceramides are required for healthy lamellar phase architecture of skin barrier lipids.
Journal of Lipid Research, 63(6), 100226.
https://doi.org/10.1016/j.jlr.2022.100226

Thomas, A.C., Cullup, T., Norgett, E.E., et al. (2006).
ABCA12 is the major harlequin ichthyosis gene and encodes a putative lipid transporter in epidermal lamellar granules.
Journal of Investigative Dermatology, 126(11), pp. 2408–2413.
https://doi.org/10.1038/sj.jid.5700455

van Smeden, J., Hoppel, L., van der Heijden, R., et al. (2011).
LC/MS analysis of stratum corneum lipids: ceramide profiling and discovery.
Journal of Lipid Research, 52(6), pp. 1211–1221.
https://doi.org/10.1194/jlr.M014456

van Smeden, J., Janssens, M., Gooris, G.S., et al. (2014).
The important role of stratum corneum lipids for the cutaneous barrier function.
Biochimica et Biophysica Acta – Molecular and Cell Biology of Lipids, 1841(3), pp. 295–313.
https://doi.org/10.1016/j.bbalip.2013.11.006

Williams, S.F., Andrew, P., Brown, K., et al. (2025).
The impact of age on the lipidomic profile of the stratum corneum and associated effects on structure, function and overall skin health in adults predisposed to atopic dermatitis.
Experimental Dermatology, 34(12), e70192.
https://doi.org/10.1111/exd.70192

Yagi, N., Kinoshita, M., Shibata, N., et al. (2020).
Microbeam X-ray diffraction study of lipid structure in stratum corneum of human skin.
PLOS ONE, 15(5), e0233131.
https://doi.org/10.1371/journal.pone.0233131

Yokose, U., Ishikawa, J., Morokuma, Y., et al. (2020).
The ceramide [NP]/[NS] ratio in the stratum corneum is a potential marker for skin properties and epidermal differentiation.
BMC Dermatology, 20(1), 6.
https://doi.org/10.1186/s12895-020-00102-1

Chapter 3

Behne, M.J., Meyer, J.W., Hanson, K.M., et al. (2002).
NHE1 regulates the stratum corneum permeability barrier homeostasis. Microenvironment acidification assessed with fluorescence lifetime imaging.
Journal of Biological Chemistry, 277(49), pp. 47399–47406.
https://doi.org/10.1074/jbc.M204759200

Brattsand, M., Stefansson, K., Lundh, C., et al. (2005).
A proteolytic cascade of kallikreins in the stratum corneum.
Journal of Investigative Dermatology, 124(1), pp. 198–203.
https://doi.org/10.1111/j.0022-202X.2004.23547.x

Caubet, C., Jonca, N., Brattsand, M., et al. (2004).
Degradation of corneodesmosome proteins by two serine proteases of the kallikrein family, SCTE/KLK5/hK5 and SCCE/KLK7/hK7.
Journal of Investigative Dermatology, 122(5), pp. 1235–1244.
https://doi.org/10.1111/j.0022-202X.2004.22512.x

Chan, A. and Mauro, T. (2011).
Acidification in the epidermis and the role of secretory phospholipases.
Dermato-Endocrinology, 3(2), pp. 84–90.
https://doi.org/10.4161/derm.3.2.15140

Chavanas, S., Bodemer, C., Rochat, A., et al. (2000).
Mutations in SPINK5, encoding a serine protease inhibitor, cause Netherton syndrome.
Nature Genetics, 25(2), pp. 141–142.
https://doi.org/10.1038/75977

Deraison, C., Bonnart, C., Lopez, F., et al. (2007).
LEKTI fragments specifically inhibit KLK5, KLK7 and KLK14 and are released in a pH-dependent manner.
Molecular Biology of the Cell, 18(9), pp. 3607–3619.
https://doi.org/10.1091/mbc.e07-02-0124

Feingold, K.R. (2007).
The role of epidermal lipids in cutaneous permeability barrier homeostasis.
Journal of Lipid Research, 48(12), pp. 2531–2546.
https://doi.org/10.1194/jlr.R700013-JLR200

Fluhr, J.W. and Elias, P.M. (2002).
Stratum corneum pH: formation and function of the ‘acid mantle’.
Exogenous Dermatology, 1(4), pp. 163–175.
https://doi.org/10.1159/000066140

Hachem, J.-P., Behne, M., Aronchik, I., et al. (2005).
Extracellular pH controls NHE1 expression in epidermis and keratinocytes: implications for barrier repair.
Journal of Investigative Dermatology, 125(4), pp. 790–797.
https://doi.org/10.1111/j.0022-202X.2005.23836.x

Hachem, J.-P., Man, M.-Q., Crumrine, D., et al. (2005).
Sustained serine proteases activity by prolonged increase in pH leads to degradation of lipid processing enzymes and profound alterations of barrier function and stratum corneum integrity.
Journal of Investigative Dermatology, 125(3), pp. 510–520.
https://doi.org/10.1111/j.0022-202X.2005.23838.x

Kumar, P. and Das, A. (2023).
Acid mantle: what we need to know.
Indian Journal of Dermatology, Venereology and Leprology, 89(5), pp. 729–732.
https://doi.org/10.25259/IJDVL_153_2022

Lambers, H., Piessens, S., Bloem, A., et al. (2006).
Natural skin surface pH is on average below 5, which is beneficial for its resident flora.
International Journal of Cosmetic Science, 28(5), pp. 359–370.
https://doi.org/10.1111/j.1467-2494.2006.00344.x

Lukić, M., Pantelić, I. and Savić, S.D. (2021).
Towards optimal pH of the skin and topical formulations: from the current state of the art to tailored products.
Cosmetics, 8(3), 69.
https://doi.org/10.3390/cosmetics8030069

Mauro, T., Holleran, W.M., Grayson, S., et al. (1998).
Barrier recovery is impeded at neutral pH, independent of ionic effects: implications for extracellular lipid processing.
Archives of Dermatological Research, 290(4), pp. 215–222.
https://doi.org/10.1007/s004030050293

Schechter, N.M., Choi, E.J., Wang, Z.M., et al. (2005).
Inhibition of human kallikreins 5 and 7 by the serine protease inhibitor lympho-epithelial Kazal-type inhibitor (LEKTI).
Biological Chemistry, 386(11), pp. 1173–1179.
https://doi.org/10.1515/BC.2005.134

Schmid-Wendtner, M.-H. and Korting, H.C. (2006).
The pH of the skin surface and its impact on the barrier function.
Skin Pharmacology and Physiology, 19(6), pp. 296–302.
https://doi.org/10.1159/000094670

Takagi, Y., Kriehuber, E., Imokawa, G., et al. (1999).
β-Glucocerebrosidase activity in mammalian stratum corneum.
Journal of Lipid Research, 40(5), pp. 861–869.
https://doi.org/10.1016/S0022-2275(20)32121-0

Chapter 4

Bouslimani, A., da Silva, R., Kosciolek, T., et al. (2019).
The impact of skin care products on skin chemistry and microbiome dynamics.
BMC Biology, 17, 47.
https://doi.org/10.1186/s12915-019-0660-6

Brauweiler, A.M., Bin, L., Kim, B.E., et al. (2013).
Filaggrin-dependent secretion of sphingomyelinase protects against Staphylococcus aureus α-toxin-induced keratinocyte death.
Journal of Allergy and Clinical Immunology, 131(2), pp. 421–427.
https://doi.org/10.1016/j.jaci.2012.10.030

Cau, L., Williams, M.R., Butcher, A.M., et al. (2021).
Staphylococcus epidermidis protease EcpA can be a deleterious component of the skin microbiome in atopic dermatitis.
Journal of Allergy and Clinical Immunology, 147(3), pp. 955–966.e16.
https://doi.org/10.1016/j.jaci.2020.06.024

Clausen, M.L., Edslev, S.M., Andersen, P.S., et al. (2017).
Staphylococcus aureus colonization in atopic eczema and its association with filaggrin gene mutations.
British Journal of Dermatology, 177(5), pp. 1394–1400.
https://doi.org/10.1111/bjd.15470

De Almeida, C.V., Antiga, E. and Lulli, M. (2023).
Oral and topical probiotics and postbiotics in skincare and dermatological therapy: a concise review.
Microorganisms, 11(6), 1420.
https://doi.org/10.3390/microorganisms11061420

Drake, D.R., Brogden, K.A., Dawson, D.V., et al. (2008).
Thematic review series: skin lipids. Antimicrobial lipids at the skin surface.
Journal of Lipid Research, 49(1), pp. 4–11.
https://doi.org/10.1194/jlr.R700016-JLR200

Dürr, U.H.N., Sudheendra, U.S. and Ramamoorthy, A. (2006).
LL-37, the only human member of the cathelicidin family of antimicrobial peptides.
Biochimica et Biophysica Acta – Biomembranes, 1758(9), pp. 1408–1425.
https://doi.org/10.1016/j.bbamem.2006.03.030

Findley, K., Oh, J., Yang, J., et al. (2013).
Topographic diversity of fungal and bacterial communities in human skin.
Nature, 498(7454), pp. 367–370.
https://doi.org/10.1038/nature12171

Grice, E.A., Kong, H.H., Conlan, S., et al. (2009).
Topographical and temporal diversity of the human skin microbiome.
Science, 324(5931), pp. 1190–1192.
https://doi.org/10.1126/science.1171700

Grice, E.A. and Segre, J.A. (2011).
The skin microbiome.
Nature Reviews Microbiology, 9(4), pp. 244–253.
https://doi.org/10.1038/nrmicro2537

Nakatsuji, T., Chen, T.H., Narala, S., et al. (2017).
Antimicrobials from human skin commensal bacteria protect against Staphylococcus aureus and are deficient in atopic dermatitis.
Science Translational Medicine, 9(378), eaah4680.
https://doi.org/10.1126/scitranslmed.aah4680

Oh, J., Byrd, A.L., Park, M., et al. (2016).
Temporal stability of the human skin microbiome.
Cell, 165(4), pp. 854–866.
https://doi.org/10.1016/j.cell.2016.04.008

Oh, J. and Voigt, A.Y. (2025).
The human skin microbiome: from metagenomes to therapeutics.
Nature Reviews Microbiology, 23(12), pp. 771–787.
https://doi.org/10.1038/s41579-025-01211-9

Ong, P.Y., Ohtake, T., Brandt, C., et al. (2002).
Endogenous antimicrobial peptides and skin infections in atopic dermatitis.
New England Journal of Medicine, 347(15), pp. 1151–1160.
https://doi.org/10.1056/NEJMoa021481

Salminen, S., Collado, M.C., Endo, A., et al. (2021).
The International Scientific Association of Probiotics and Prebiotics (ISAPP) consensus statement on the definition and scope of postbiotics.
Nature Reviews Gastroenterology & Hepatology, 18(9), pp. 649–667.
https://doi.org/10.1038/s41575-021-00440-6

Uberoi, A., Bartow-McKenney, C., Zheng, Q., et al. (2021).
Commensal microbiota regulates skin barrier function and repair via signaling through the aryl hydrocarbon receptor.
Cell Host & Microbe, 29(8), pp. 1235–1248.e8.
https://doi.org/10.1016/j.chom.2021.05.011

Williams, M.R., Costa, S.K., Zaramela, L.S., et al. (2019).
Quorum sensing between bacterial species on the skin protects against atopic dermatitis and skin inflammation.
Science Translational Medicine, 11(490), eaat8329.
https://doi.org/10.1126/scitranslmed.aat8329

Yamasaki, K., Di Nardo, A., Bardan, A., et al. (2007).
Increased serine protease activity and cathelicidin promotes skin inflammation in rosacea.
Nature Medicine, 13(8), pp. 975–980.
https://doi.org/10.1038/nm1616

Zheng, Y., Hunt, R.L., Villaruz, A.E., et al. (2022).
Commensal Staphylococcus epidermidis contributes to skin barrier homeostasis by generating protective ceramides.
Cell Host & Microbe, 30(3), pp. 301–313.e9.
https://doi.org/10.1016/j.chom.2022.01.004

Chapter 5

Arif, T. (2015).
Salicylic acid as a peeling agent: a comprehensive review.
Clinical, Cosmetic and Investigational Dermatology, 8, pp. 455–461.
https://doi.org/10.2147/CCID.S84765

Bommannan, D., Potts, R.O. and Guy, R.H. (1991).
Examination of the effect of ethanol on human stratum corneum in vivo using infrared spectroscopy.
Journal of Controlled Release, 16(3), pp. 299–304.
https://doi.org/10.1016/0168-3659(91)90006-Y

Bylka, W., Znajdek-Awiżeń, P., Studzińska-Sroka, E., et al. (2013).
Centella asiatica in cosmetology.
Postępy Dermatologii i Alergologii, 30(1), pp. 46–49.
https://doi.org/10.5114/pdia.2013.33378

De Paepe, K., Roseeuw, D. and Rogiers, V. (2002).
Repair of acetone- and sodium lauryl sulphate-damaged human skin barrier function using topically applied emulsions containing barrier lipids.
Journal of the European Academy of Dermatology and Venereology, 16(6), pp. 587–594.
https://doi.org/10.1046/j.1468-3083.2002.00527.x

Di Nardo, A., Sugino, K., Wertz, P., et al. (1996).
Sodium lauryl sulfate (SLS) induced irritant contact dermatitis: a correlation study between ceramides and in vivo parameters of irritation.
Contact Dermatitis, 35(2), pp. 86–91.
https://doi.org/10.1111/j.1600-0536.1996.tb02296.x

Draelos, Z.D., Ertel, K.D. and Berge, C.A. (2006).
Facilitating facial retinization through barrier improvement.
Cutis, 78(4), pp. 275–281.
No DOI available.

Feng, X., Shang, J., Wang, Y., et al. (2025).
Exploring the properties and application potential of β-glucan in skin care.
Food Science & Nutrition, 13(4), e70212.
https://doi.org/10.1002/fsn3.70212

Gabard, B., Eisner, P. and Treffel, P. (1996).
Barrier function of the skin in a repetitive irritation model and influence of 2 different treatments.
Skin Research and Technology, 2(2), pp. 78–82.
https://doi.org/10.1111/j.1600-0846.1996.tb00063.x

Gehring, W. and Gloor, M. (2000).
Effect of topically applied dexpanthenol on epidermal barrier function and stratum corneum hydration.
Arzneimittel-Forschung / Drug Research, 50(7), pp. 659–663.
https://doi.org/10.1055/s-0031-1300268

Goyette, P., Chen, C.F., Wang, W., et al. (2000).
Characterization of retinoic acid receptor-deficient keratinocytes.
Journal of Biological Chemistry, 275(22), pp. 16497–16505.
https://doi.org/10.1074/jbc.M909382199

Grether-Beck, S., Felsner, I., Brenden, H., et al. (2012).
Urea uptake enhances barrier function and antimicrobial defense in humans by regulating epidermal gene expression.
Journal of Investigative Dermatology, 132(6), pp. 1561–1572.
https://doi.org/10.1038/jid.2012.42

Horikoshi, T., Matsumoto, M., Usuki, A., et al. (2005).
Effects of glycolic acid on desquamation-regulating proteinases in human stratum corneum.
Experimental Dermatology, 14(1), pp. 34–40.
https://doi.org/10.1111/j.0906-6705.2005.00224.x

Huth, S., Marquardt, Y., Huth, L., et al. (2021).
Molecular effects of photon irradiation and subsequent aftercare treatment with dexpanthenol-containing ointment or liquid in 3D models of human skin and non-keratinized oral mucosa.
Experimental Dermatology, 30(5), pp. 745–750.
https://doi.org/10.1111/exd.14266

Jing, R., Fu, M., Huang, Y., et al. (2024).
Oat β-glucan repairs the epidermal barrier by upregulating the levels of epidermal differentiation, cell–cell junctions and lipids via Dectin-1.
British Journal of Pharmacology, 181(11), pp. 1596–1613.
https://doi.org/10.1111/bph.16306

Kim, E., Kim, S., Nam, G.W., et al. (2009).
The alkaline pH-adapted skin barrier is disrupted severely by SLS-induced irritation.
International Journal of Cosmetic Science, 31(4), pp. 263–269.
https://doi.org/10.1111/j.1468-2494.2009.00491.x

Kligman, A.M., Grove, G.L., Hirose, R., et al. (1986).
Topical tretinoin for photoaged skin.
Journal of the American Academy of Dermatology, 15(4 Pt 2), pp. 836–859.
https://doi.org/10.1016/S0190-9622(86)70242-9

Kowalska, A. and Kalinowska-Lis, U. (2019).
18β-Glycyrrhetinic acid: its core biological properties and dermatological applications.
International Journal of Cosmetic Science, 41(4), pp. 325–331.
https://doi.org/10.1111/ics.12548

Kwak, S., Brief, E., Langlais, D., et al. (2012).
Ethanol perturbs lipid organization in models of stratum corneum membranes: an investigation combining differential scanning calorimetry, infrared and (2)H NMR spectroscopy.
Biochimica et Biophysica Acta – Biomembranes, 1818(5), pp. 1410–1419.
https://doi.org/10.1016/j.bbamem.2012.02.013

Mastrofrancesco, A., Ottaviani, M., Aspite, N., et al. (2010).
Azelaic acid modulates the inflammatory response in normal human keratinocytes through PPARγ activation.
Experimental Dermatology, 19(9), pp. 813–820.
https://doi.org/10.1111/j.1600-0625.2010.01107.x

Mohammed, D., Crowther, J.M., Matts, P.J., et al. (2013).
Influence of niacinamide containing formulations on the stratum corneum and barrier function in vivo.
International Journal of Pharmaceutics, 441(1–2), pp. 192–201.
https://doi.org/10.1016/j.ijpharm.2012.11.043

Proksch, E. and Nissen, H.P. (2002).
Dexpanthenol enhances skin barrier repair and reduces inflammation after sodium lauryl sulphate-induced irritation.
Journal of Dermatological Treatment, 13(4), pp. 173–178.
https://doi.org/10.1080/09546630212345674

Sur, R., Nigam, A., Grote, D., et al. (2008).
Avenanthramides, polyphenols from oats, exhibit anti-inflammatory and anti-itch activity.
Archives of Dermatological Research, 300(10), pp. 569–574.
https://doi.org/10.1007/s00403-008-0858-x

Tanno, O., Ota, Y., Kitamura, N., et al. (2000).
Nicotinamide increases biosynthesis of ceramides as well as other stratum corneum lipids to improve the epidermal permeability barrier.
British Journal of Dermatology, 143(3), pp. 524–531.
https://doi.org/10.1111/j.1365-2133.2000.03705.x

Törmä, H., Lindberg, M. and Berne, B. (2008).
Skin barrier disruption by sodium lauryl sulfate-exposure alters the expressions of involucrin, transglutaminase 1, profilaggrin, and kallikreins during the repair phase in human skin in vivo.
Journal of Investigative Dermatology, 128(5), pp. 1212–1219.
https://doi.org/10.1038/sj.jid.5701170

Trevisol, T.C., Henriques, R.O., Souza, A.J.A., et al. (2022).
An overview of the use of proteolytic enzymes as exfoliating agents.
Journal of Cosmetic Dermatology, 21(8), pp. 3300–3307.
https://doi.org/10.1111/jocd.14673

Vidal, S.I., Menta, N. and Friedman, A. (2025).
All things acid: a primer on alpha hydroxy, beta hydroxy, and polyhydroxy acids.
Journal of Drugs in Dermatology, 24(5), pp. 549–550.
https://doi.org/10.36849/JDD.8502T1

Vollberg, T.M., Nervi, C., George, M.D., et al. (1992).
Retinoic acid receptors as regulators of human epidermal keratinocyte differentiation.
Molecular Endocrinology, 6(5), pp. 667–676.
https://doi.org/10.1210/mend.6.5.1318502

Chapter 6

Bautista, D.M., Jordt, S.E., Nikai, T., et al. (2006).
TRPA1 mediates the inflammatory actions of environmental irritants and proalgesic agents.
Cell, 124(6), pp. 1269–1282.
https://doi.org/10.1016/j.cell.2006.02.023

Blank, I.H. (1952).
Factors which influence the water content of the stratum corneum.
Journal of Investigative Dermatology, 18(6), pp. 433–440.
https://doi.org/10.1038/jid.1952.52

Caterina, M.J., Schumacher, M.A., Tominaga, M., et al. (1997).
The capsaicin receptor: a heat-activated ion channel in the pain pathway.
Nature, 389(6653), pp. 816–824.
https://doi.org/10.1038/39807

Évora, A.S., Zhang, Z., Johnson, S.A., et al. (2024).
The effects of hydration on the topographical and mechanical properties of corneocytes.
Journal of the Mechanical Behavior of Biomedical Materials, 150, 106296.
https://doi.org/10.1016/j.jmbbm.2023.106296

Ghadially, R., Halkier-Sørensen, L. and Elias, P.M. (1992).
Effects of petrolatum on stratum corneum structure and function.
Journal of the American Academy of Dermatology, 26(3 Pt 2), pp. 387–396.
https://doi.org/10.1016/0190-9622(92)70060-S

Gloor, M., Senger, B., Langenauer, M., et al. (2004).
On the course of the irritant reaction after irritation with sodium lauryl sulphate.
Skin Research and Technology, 10(3), pp. 144–148.
https://doi.org/10.1111/j.1600-0846.2004.00074.x

Halprin, K.M. (1972).
Epidermal ‘turnover time’ — a re-examination.
British Journal of Dermatology, 86(1), pp. 14–19.
https://doi.org/10.1111/j.1365-2133.1972.tb01886.x

Chapter 7

Andrew, P.V., Williams, S.F., Brown, K., et al. (2025).
Topical supplementation with physiological lipids rebalances the stratum corneum ceramide profile and strengthens skin barrier function in adults predisposed to atopic dermatitis.
British Journal of Dermatology, 193(4), pp. 729–740.
https://doi.org/10.1093/bjd/ljaf200

Berkers, T., Visscher, D., Gooris, G.S., et al. (2018).
Topically applied ceramides interact with the stratum corneum lipid matrix in compromised ex vivo skin.
Pharmaceutical Research, 35(3), 48.
https://doi.org/10.1007/s11095-017-2288-y

Blank, I.H. (1952).
Factors which influence the water content of the stratum corneum.
Journal of Investigative Dermatology, 18(6), pp. 433–440.
https://doi.org/10.1038/jid.1952.52

Bouwstra, J.A., Gooris, G.S., Dubbelaar, F.E.R., et al. (2001).
Phase behavior of lipid mixtures based on human ceramides: coexistence of crystalline and liquid phases.
Journal of Lipid Research, 42(11), pp. 1759–1770.
https://doi.org/10.1016/S0022-2275(20)31502-9

Elias, P.M. (2005).
Stratum corneum defensive functions: an integrated view.
Journal of Investigative Dermatology, 125(2), pp. 183–200.
https://doi.org/10.1111/j.0022-202X.2005.23668.x

Feingold, K.R. (2007).
The role of epidermal lipids in cutaneous permeability barrier homeostasis.
Journal of Lipid Research, 48(12), pp. 2531–2546.
https://doi.org/10.1194/jlr.R700013-JLR200

Fluhr, J.W., Kao, J., Jain, M., et al. (2001).
Generation of free fatty acids from phospholipids regulates stratum corneum acidification and integrity.
Journal of Investigative Dermatology, 117(1), pp. 44–51.
https://doi.org/10.1046/j.0022-202x.2001.01399.x

Fluhr, J.W., Darlenski, R. and Surber, C. (2008).
Glycerol and the skin: holistic approach to barrier function and hydration.
British Journal of Dermatology, 159(1), pp. 23–34.
https://doi.org/10.1111/j.1365-2133.2008.08643.x

Fluhr, J.W., Darlenski, R., Daehnhardt-Pfeiffer, S., et al. (2024).
Impact of multilamellar formulations on stratum corneum lipid organization and epidermal lipid barrier enhancement (Part II).
International Journal of Cosmetic Science, 46(4), pp. 578–589.
https://doi.org/10.1111/ics.12971

Hara, M., Ma, T. and Verkman, A.S. (2002).
Selectively reduced glycerol in skin of aquaporin-3-deficient mice may account for impaired skin hydration, elasticity, and barrier recovery.
Journal of Biological Chemistry, 277(48), pp. 46616–46621.
https://doi.org/10.1074/jbc.M209003200

Hara, M. and Verkman, A.S. (2003).
Glycerol replacement corrects defective skin hydration, elasticity, and barrier function in aquaporin-3-deficient mice.
Proceedings of the National Academy of Sciences of the United States of America, 100(12), pp. 7360–7365.
https://doi.org/10.1073/pnas.1230416100

Hara-Chikuma, M. and Verkman, A.S. (2008).
Roles of aquaporin-3 in the epidermis.
Journal of Investigative Dermatology, 128(9), pp. 2145–2151.
https://doi.org/10.1038/jid.2008.70

Holleran, W.M., Takagi, Y., Menon, G.K., et al. (1993).
Processing of epidermal glucosylceramides is required for optimal mammalian cutaneous permeability barrier function.
Journal of Clinical Investigation, 91(4), pp. 1656–1664.
https://doi.org/10.1172/JCI116374

Imokawa, G., Abe, A., Jin, K., et al. (1991).
Decreased level of ceramides in stratum corneum of atopic dermatitis: an etiologic factor in atopic dry skin?
Journal of Investigative Dermatology, 96(4), pp. 523–526.
https://doi.org/10.1111/1523-1747.ep12470233

Man, M.Q., Feingold, K.R., Thornfeldt, C.R., et al. (1996).
Optimization of physiological lipid mixtures for barrier repair.
Journal of Investigative Dermatology, 106(5), pp. 1096–1101.
https://doi.org/10.1111/1523-1747.ep12340135

Norlén, L. (2001).
Skin barrier formation: the membrane folding model.
Journal of Investigative Dermatology, 117(4), pp. 823–829.
https://doi.org/10.1046/j.0022-202x.2001.01445.x

Oranje, A.P., Devillers, A.C.A., Kunz, B., et al. (2006).
Treatment of patients with atopic dermatitis using wet-wrap dressings with diluted steroids and/or emollients: An expert panel’s opinion and review of the literature.
Journal of the European Academy of Dermatology and Venereology, 20(10), pp. 1277–1286.
https://doi.org/10.1111/j.1468-3083.2006.01790.x

Rawlings, A.V. and Harding, C.R. (2004).
Moisturization and skin barrier function.
Dermatologic Therapy, 17(Suppl 1), pp. 43–48.
https://doi.org/10.1111/j.1396-0296.2004.04s1005.x

Rojek, A., Praetorius, J., Frøkiaer, J., et al. (2008).
A current view of the mammalian aquaglyceroporins.
Annual Review of Physiology, 70, pp. 301–327.
https://doi.org/10.1146/annurev.physiol.70.113006.100452

Shin, K.-O., Mihara, H., Ishida, K., et al. (2022).
Exogenous ceramide serves as a precursor to endogenous ceramide synthesis and as a modulator of keratinocyte differentiation.
Cells, 11(11), 1742.
https://doi.org/10.3390/cells11111742

Chapter 8

Ali, S.M. and Yosipovitch, G. (2013).
Skin pH: from basic science to basic skin care.
Acta Dermato-Venereologica, 93(3), pp. 261–267.
https://doi.org/10.2340/00015555-1531

Blaak, J. and Staib, P. (2018).
The relation of pH and skin cleansing.
Current Problems in Dermatology, 54, pp. 132–142.
https://doi.org/10.1159/000489527

Bouwstra, J.A., Gooris, G.S., Dubbelaar, F.E., et al. (1999).
Cholesterol sulfate and calcium affect stratum corneum lipid organization over a wide temperature range.
Journal of Lipid Research, 40(12), pp. 2303–2312.
https://doi.org/10.1016/S0022-2275(20)32105-2

Chaumont, A., Voisin, C., Sardella, A., et al. (2012).
Interactions between domestic water hardness, infant swimming and atopy in the development of childhood eczema.
Environmental Research, 116, pp. 52–57.
https://doi.org/10.1016/j.envres.2012.04.013

Choi, E.H., Man, M.Q., Xu, P., et al. (2007).
Stratum corneum acidification is impaired in moderately aged human and murine skin.
Journal of Investigative Dermatology, 127(12), pp. 2847–2856.
https://doi.org/10.1038/sj.jid.5700913

Danby, S.G., Brown, K., Higgs-Bayliss, T., et al. (2018).
The effect of water hardness on surfactant deposition after washing and subsequent skin irritation in atopic dermatitis patients and healthy control subjects.
Journal of Investigative Dermatology, 138(1), pp. 68–77.
https://doi.org/10.1016/j.jid.2017.08.037

Elias, P.M. (2017).
The how, why and clinical importance of stratum corneum acidification.
Experimental Dermatology, 26(11), pp. 999–1003.
https://doi.org/10.1111/exd.13329

Engebretsen, K.A., Bager, P., Wohlfahrt, J., et al. (2017).
Prevalence of atopic dermatitis in infants by domestic water hardness and season of birth: cohort study.
Journal of Allergy and Clinical Immunology, 139(5), pp. 1568–1574.e1.
https://doi.org/10.1016/j.jaci.2016.11.021

Fürtjes, T., Kottner, J., Blume-Peytavi, U., et al. (2017).
Impact of a pH 5 oil-in-water emulsion on skin surface pH regeneration after alkalization.
Skin Pharmacology and Physiology, 30(3), pp. 141–147.
https://doi.org/10.1159/000475879

Hawkins, S., Dasgupta, B.R. and Ananthapadmanabhan, K.P. (2021).
Role of pH in skin cleansing.
International Journal of Cosmetic Science, 43(4), pp. 474–483.
https://doi.org/10.1111/ics.12721

Jabbar-Lopez, Z.K., Craven, J., Logan, K., et al. (2020).
Longitudinal analysis of the effect of water hardness on atopic eczema: evidence for gene–environment interaction.
British Journal of Dermatology, 183(2), pp. 285–293.
https://doi.org/10.1111/bjd.18597

Jabbar-Lopez, Z.K., Ung, C.Y., Alexander, H., et al. (2021).
The effect of water hardness on atopic eczema and skin barrier function: a systematic review and meta-analysis.
Clinical & Experimental Allergy, 51(3), pp. 430–451.
https://doi.org/10.1111/cea.13797

Lopez, D.J., Singh, A., Waidyatillake, N.T., et al. (2022).
The association between domestic hard water and eczema in adults from the UK Biobank cohort study.
British Journal of Dermatology, 187(5), pp. 704–712.
https://doi.org/10.1111/bjd.21771

Thomas, K.S., Koller, K., Dean, T., et al. (2011).
A multicentre randomised controlled trial and economic evaluation of ion-exchange water softeners for the treatment of eczema in children: the Softened Water Eczema Trial (SWET).
Health Technology Assessment, 15(8), pp. 1–156.
https://doi.org/10.3310/hta15080

Warren, R., Ertel, K.D., Bartolo, R.G., et al. (1996).
The influence of hard water (calcium) and surfactants on irritant contact dermatitis.
Contact Dermatitis, 35(6), pp. 337–343.
https://doi.org/10.1111/j.1600-0536.1996.tb02414.x

Chapter 9

Barresi, R., Dumbuya, H., Liao, I.C., et al. (2022).
Alteration to the skin ceramide profile following broad-spectrum UV exposure.
Journal of Drugs in Dermatology, 21(1), pp. 77–85.
https://doi.org/10.36849/JDD.6331

Biniek, K., Levi, K. and Dauskardt, R.H. (2012).
Solar UV radiation reduces the barrier function of human skin.
Proceedings of the National Academy of Sciences of the United States of America, 109(42), pp. 17111–17116.
https://doi.org/10.1073/pnas.1206851109

Boncheva, M., Damien, F. and Normand, V. (2008).
Molecular organization of the lipid matrix in intact Stratum corneum using ATR-FTIR spectroscopy.
Biochimica et Biophysica Acta – Biomembranes, 1778(5), pp. 1344–1355.
https://doi.org/10.1016/j.bbamem.2008.01.022

Cau, L., Pendaries, V., Lhuillier, E., et al. (2017).
Lowering relative humidity level increases epidermal protein deimination and drives human filaggrin breakdown.
Journal of Dermatological Science, 86(2), pp. 106–113.
https://doi.org/10.1016/j.jdermsci.2017.02.280

Egawa, M., Oguri, M., Kuwahara, T., et al. (2002).
Effect of exposure of human skin to a dry environment.
Skin Research and Technology, 8(4), pp. 212–218.
https://doi.org/10.1034/j.1600-0846.2002.00351.x

Engebretsen, K.A., Johansen, J.D., Kezic, S., et al. (2016).
The effect of environmental humidity and temperature on skin barrier function and dermatitis.
Journal of the European Academy of Dermatology and Venereology, 30(2), pp. 223–249.
https://doi.org/10.1111/jdv.13301

Guéhenneux, S., Gardinier, S., Morizot, F., et al. (2012).
Skin surface hydration decreases rapidly during long distance flights.
Skin Research and Technology, 18(2), pp. 238–240.
https://doi.org/10.1111/j.1600-0846.2011.00560.x

He, Q.C., Tavakkol, A., Wietecha, K., et al. (2006).
Effects of environmentally realistic levels of ozone on stratum corneum function.
International Journal of Cosmetic Science, 28(5), pp. 349–357.
https://doi.org/10.1111/j.1467-2494.2006.00347.x

Jungersted, J.M., Høgh, J.K., Hellgren, L.I., et al. (2011).
The impact of ultraviolet therapy on stratum corneum ceramides and barrier function.
Photodermatology, Photoimmunology & Photomedicine, 27(6), pp. 331–333.
https://doi.org/10.1111/j.1600-0781.2011.00618.x

Katagiri, C., Sato, J., Nomura, J., et al. (2003).
Changes in environmental humidity affect the water-holding property of the stratum corneum and its free amino acid content, and the expression of filaggrin in the epidermis of hairless mice.
Journal of Dermatological Science, 31(1), pp. 29–35.
https://doi.org/10.1016/S0923-1811(02)00137-8

Kavanagh, G.M., Crosby, J.R. and Norval, M. (1995).
Urocanic acid isomers in human skin: analysis of site variation.
British Journal of Dermatology, 133(5), pp. 728–732.
https://doi.org/10.1111/j.1365-2133.1995.tb02746.x

Kezic, S., Kemperman, P.M.J.H., Koster, E.S., et al. (2008).
Loss-of-function mutations in the filaggrin gene lead to reduced level of natural moisturizing factor in the stratum corneum.
Journal of Investigative Dermatology, 128(8), pp. 2117–2119.
https://doi.org/10.1038/jid.2008.29

Kim, B.E., Kim, J., Goleva, E., et al. (2021).
Particulate matter causes skin barrier dysfunction.
JCI Insight, 6(5), e145185.
https://doi.org/10.1172/jci.insight.145185

Krutmann, J., Schikowski, T., Morita, A., et al. (2014).
Pollution and skin: from epidemiological and mechanistic studies to clinical implications.
Journal of Dermatological Science, 76(3), pp. 163–168.
https://doi.org/10.1016/j.jdermsci.2014.08.008

McLoone, P., Simics, E., Barton, A., et al. (2005).
An action spectrum for the production of cis-urocanic acid in human skin in vivo.
Journal of Investigative Dermatology, 124(5), pp. 1071–1074.
https://doi.org/10.1111/j.0022-202X.2005.23731.x

Petracca, B., Pirot, F., Bonté, F., et al. (2021).
Effects of ozone on stratum corneum lipid integrity and assembly.
Chemistry and Physics of Lipids, 239, 105121.
https://doi.org/10.1016/j.chemphyslip.2021.105121

Pham, D.M., Boussouira, B., Moyal, D., et al. (2015).
Oxidization of squalene, a human skin lipid: a new and reliable marker of environmental pollution studies.
International Journal of Cosmetic Science, 37(4), pp. 357–365.
https://doi.org/10.1111/ics.12208

Ryu, Y.S., Kang, K.A., Piao, M.J., et al. (2019).
Particulate matter-induced senescence of skin keratinocytes involves oxidative stress-dependent epigenetic modifications.
Experimental & Molecular Medicine, 51(9), 108.
https://doi.org/10.1038/s12276-019-0305-4

Sandford, E., Chen, Y., Hunter, I., et al. (2013).
Capturing skin properties from dynamic mechanical analyses.
Skin Research and Technology, 19(1), pp. e339–e348.
https://doi.org/10.1111/j.1600-0846.2012.00649.x

Thiele, J.J., Traber, M.G. and Packer, L. (1998).
Depletion of human stratum corneum vitamin E: an early and sensitive in vivo marker of UV induced photo-oxidation.
Journal of Investigative Dermatology, 110(5), pp. 756–761.
https://doi.org/10.1046/j.1523-1747.1998.00169.x

Thiele, J.J., Schroeter, C., Hsieh, S.N., et al. (2001).
The antioxidant network of the stratum corneum.
Current Problems in Dermatology, 29, pp. 26–42.
https://doi.org/10.1159/000060651

Valacchi, G., Weber, S.U., Luu, C., et al. (2000).
Ozone potentiates vitamin E depletion by ultraviolet radiation in the murine stratum corneum.
FEBS Letters, 466(1), pp. 165–168.
https://doi.org/10.1016/S0014-5793(99)01787-1

Valacchi, G., van der Vliet, A., Schock, B.C., et al. (2002).
Ozone exposure activates oxidative stress responses in murine skin.
Toxicology, 179(1–2), pp. 163–170.
https://doi.org/10.1016/S0300-483X(02)00240-8

Valacchi, G., Pagnin, E., Corbacho, A.M., et al. (2004).
In vivo ozone exposure induces antioxidant/stress-related responses in murine lung and skin.
Free Radical Biology and Medicine, 36(5), pp. 673–681.
https://doi.org/10.1016/j.freeradbiomed.2003.12.005

Vierkötter, A., Schikowski, T., Ranft, U., et al. (2010).
Airborne particle exposure and extrinsic skin aging.
Journal of Investigative Dermatology, 130(12), pp. 2719–2726.
https://doi.org/10.1038/jid.2010.204

Vogel, C.F.A., Van Winkle, L.S., Esser, C., et al. (2020).
The aryl hydrocarbon receptor as a target of environmental stressors – implications for pollution mediated stress and inflammatory responses.
Redox Biology, 34, 101530.
https://doi.org/10.1016/j.redox.2020.101530

Walterscheid, J.P., Nghiem, D.X., Kazimi, N., et al. (2006).
Cis-urocanic acid, a sunlight-induced immunosuppressive factor, activates immune suppression via the 5-HT2A receptor.
Proceedings of the National Academy of Sciences of the United States of America, 103(46), pp. 17420–17425.
https://doi.org/10.1073/pnas.0603119103

Warner, R.R., Boissy, Y.L., Lilly, N.A., et al. (1999).
Water disrupts stratum corneum lipid lamellae: damage is similar to surfactants.
Journal of Investigative Dermatology, 113(6), pp. 960–966.
https://doi.org/10.1046/j.1523-1747.1999.00774.x

Wisthaler, A. and Weschler, C.J. (2010).
Reactions of ozone with human skin lipids: sources of carbonyls, dicarbonyls, and hydroxycarbonyls in indoor air.
Proceedings of the National Academy of Sciences of the United States of America, 107(15), pp. 6568–6575.
https://doi.org/10.1073/pnas.0904498106

Chapter 10

Altemus, M., Rao, B., Dhabhar, F.S., et al. (2001).
Stress-induced changes in skin barrier function in healthy women.
Journal of Investigative Dermatology, 117(2), pp. 309–317.
https://doi.org/10.1046/j.1523-1747.2001.01373.x

Bikle, D.D. (2011).
Vitamin D metabolism and function in the skin.
Molecular and Cellular Endocrinology, 347(1–2), pp. 80–89.
https://doi.org/10.1016/j.mce.2011.05.017

Brand, R.M., Stottlemyer, J.M., Paglia, M.C., et al. (2021).
Ethanol consumption synergistically increases ultraviolet radiation induced skin damage and immune dysfunction.
Journal of Dermatological Science, 101(1), pp. 40–48.
https://doi.org/10.1016/j.jdermsci.2020.11.001

Burr, G.O. and Burr, M.M. (1929).
A new deficiency disease produced by the rigid exclusion of fat from the diet.
Journal of Biological Chemistry, 82(2), pp. 345–367.
https://doi.org/10.1016/S0021-9258(20)78281-5

Choe, S.J., Kim, D., Kim, E.J., et al. (2018).
Psychological stress deteriorates skin barrier function by activating 11β-hydroxysteroid dehydrogenase 1 and the HPA axis.
Scientific Reports, 8(1), 6334.
https://doi.org/10.1038/s41598-018-24653-z

Conti, A., Rogers, J., Verdejo, P., et al. (1996).
Seasonal influences on stratum corneum ceramide 1 fatty acids and the influence of topical essential fatty acids.
International Journal of Cosmetic Science, 18(1), pp. 1–12.
https://doi.org/10.1111/j.1467-2494.1996.tb00131.x

Dall’Oglio, F., Nasca, M.R., Fiorentini, F., et al. (2021).
Diet and acne: review of the evidence from 2009 to 2020.
International Journal of Dermatology, 60(6), pp. 672–685.
https://doi.org/10.1111/ijd.15390

Darvin, M.E., Sterry, W., Lademann, J., et al. (2013).
Alcohol consumption decreases the protection efficiency of the antioxidant network and increases the risk of sunburn in human skin.
Skin Pharmacology and Physiology, 26(1), pp. 45–51.
https://doi.org/10.1159/000343908

Denda, M., Tsuchiya, T., Hosoi, J., et al. (1998).
Immobilization-induced and crowded environment-induced stress delay barrier recovery in murine skin.
British Journal of Dermatology, 138(5), pp. 780–785.
https://doi.org/10.1046/j.1365-2133.1998.02213.x

Denda, M. and Tsuchiya, T. (2000).
Barrier recovery rate varies time-dependently in human skin.
British Journal of Dermatology, 142(5), pp. 881–884.
https://doi.org/10.1046/j.1365-2133.2000.03466.x

Elias, P.M. and Brown, B.E. (1978).
The mammalian cutaneous permeability barrier: defective barrier function in essential fatty acid deficiency correlates with abnormal intercellular lipid deposition.
Laboratory Investigation, 39(6), pp. 574–583.
No DOI available.

Elias, P.M., Brown, B.E. and Ziboh, V.A. (1980).
The permeability barrier in essential fatty acid deficiency: evidence for a direct role for linoleic acid in barrier function.
Journal of Investigative Dermatology, 74(4), pp. 230–233.
https://doi.org/10.1111/1523-1747.ep12541775

Gaddameedhi, S., Selby, C.P., Kaufmann, W.K., et al. (2011).
Control of skin cancer by the circadian rhythm.
Proceedings of the National Academy of Sciences of the United States of America, 108(46), pp. 18790–18795.
https://doi.org/10.1073/pnas.1115249108

Gardiner, C., Weakley, J., Burke, L.M., et al. (2025).
The effect of alcohol on subsequent sleep in healthy adults: a systematic review and meta-analysis.
Sleep Medicine Reviews, 80, 102030.
https://doi.org/10.1016/j.smrv.2024.102030

Hirabayashi, T., Anjo, T., Kaneko, A., et al. (2017).
PNPLA1 has a crucial role in skin barrier function by directing acylceramide biosynthesis.
Nature Communications, 8, 14609.
https://doi.org/10.1038/ncomms14609

Jacobi, U., Bartoll, J., Sterry, W., et al. (2005).
Orally administered ethanol: transepidermal pathways and effects on the human skin barrier.
Archives of Dermatological Research, 296(7), pp. 332–338.
https://doi.org/10.1007/s00403-004-0526-8

Kao, J.S., Fluhr, J.W., Man, M.Q., et al. (2003).
Short-term glucocorticoid treatment compromises both permeability barrier homeostasis and stratum corneum integrity: inhibition of epidermal lipid synthesis accounts for functional abnormalities.
Journal of Investigative Dermatology, 120(3), pp. 456–464.
https://doi.org/10.1046/j.1523-1747.2003.12053.x

Kendall, A.C., Pilkington, S.M., Wray, J.R., et al. (2022).
Menopause induces changes to the stratum corneum ceramide profile, which are prevented by hormone replacement therapy.
Scientific Reports, 12(1), 21715.
https://doi.org/10.1038/s41598-022-26095-0

Kleemann, J., Haferkamp, S., Weis, M., et al. (2024).
Alcohol promotes lipogenesis in sebocytes — implications for acne.
Cells, 13(4), 328.
https://doi.org/10.3390/cells13040328

Liu, G.Y. and Sabatini, D.M. (2020).
mTOR at the nexus of nutrition, growth, ageing and disease.
Nature Reviews Molecular Cell Biology, 21(4), pp. 183–203.
https://doi.org/10.1038/s41580-019-0199-y

Matsunaga, N., Itcho, K., Hamamura, K., et al. (2014).
24-hour rhythm of aquaporin-3 function in the epidermis is regulated by molecular clocks.
Journal of Investigative Dermatology, 134(6), pp. 1636–1644.
https://doi.org/10.1038/jid.2014.13

Mirdamadi, Y., Thielitz, A., Wiede, A., et al. (2015).
Insulin and insulin-like growth factor-1 can modulate the phosphoinositide-3-kinase/Akt/FoxO1 pathway in SZ95 sebocytes in vitro.
Molecular and Cellular Endocrinology, 415, pp. 32–44.
https://doi.org/10.1016/j.mce.2015.08.001

Mortimer, T., Zinna, V.M., Atalay, M., et al. (2024).
The epidermal circadian clock integrates and subverts brain signals to guarantee skin homeostasis.
Cell Stem Cell, 31(6), pp. 834–849.
https://doi.org/10.1016/j.stem.2024.04.013

Ogawa, Y., Kinoshita, M., Shimada, S., et al. (2018).
Zinc and skin disorders.
Nutrients, 10(2), 199.
https://doi.org/10.3390/nu10020199

Oyetakin-White, P., Suggs, A., Koo, B., et al. (2015).
Does poor sleep quality affect skin ageing and function?
Clinical and Experimental Dermatology, 40(1), pp. 17–22.
https://doi.org/10.1111/ced.12455

Palma, L., Marques, L.T., Bujan, J., et al. (2015).
Dietary water affects human skin hydration and biomechanics.
Clinical, Cosmetic and Investigational Dermatology, 8, pp. 413–421.
https://doi.org/10.2147/CCID.S86822

Plikus, M.V., Van Spyk, E.N., Pham, K., et al. (2015).
The circadian clock in skin: implications for adult stem cells, tissue homeostasis, and cosmetic applications.
Journal of Biological Rhythms, 30(3), pp. 163–182.
https://doi.org/10.1177/0748730414563537

Proksch, E., Feingold, K.R. and Elias, P.M. (1992).
Epidermal HMG CoA reductase activity in essential fatty acid deficiency: barrier requirements rather than eicosanoid generation regulate cholesterol synthesis.
Journal of Investigative Dermatology, 99(2), pp. 216–220.
https://doi.org/10.1111/1523-1747.ep12650440

Reynolds, R.V., Yeung, H., Cheng, C.E., et al. (2024).
Guidelines of care for the management of acne vulgaris.
Journal of the American Academy of Dermatology, 90(5), pp. 1006.e1–1006.e30.
https://doi.org/10.1016/j.jaad.2023.12.017

Robles, T.F. (2007).
Stress, social support, and delayed skin barrier recovery.
Psychosomatic Medicine, 69(8), pp. 807–815.
https://doi.org/10.1097/PSY.0b013e318157b12e

Saxton, R.A. and Sabatini, D.M. (2017).
mTOR signaling in growth, metabolism, and disease.
Cell, 168(6), pp. 960–976.
https://doi.org/10.1016/j.cell.2017.02.004

Smith, R.N., Mann, N.J., Braue, A., et al. (2007).
A low-glycemic-load diet improves symptoms in acne vulgaris patients: a randomized controlled trial.
American Journal of Clinical Nutrition, 86(1), pp. 107–115.
https://doi.org/10.1093/ajcn/86.1.107

Smith, T.M., Gilliland, K., Clawson, G.A., et al. (2008).
IGF-1 induces SREBP-1 expression and lipogenesis in SEB-1 sebocytes via activation of the phosphoinositide 3-kinase/Akt pathway.
Journal of Investigative Dermatology, 128(5), pp. 1286–1293.
https://doi.org/10.1038/sj.jid.5701155

Smith, T.J., Young, A.J., Karl, J.P., et al. (2018).
Impact of sleep restriction on local immune response and skin barrier restoration with and without ‘multinutrient’ nutrition intervention.
Journal of Applied Physiology, 124(1), pp. 190–200.
https://doi.org/10.1152/japplphysiol.00547.2017

Spörl, F., Korge, S., Jürchott, K., et al. (2012).
Krüppel-like factor 9 is a circadian transcription factor in human epidermis that controls proliferation of keratinocytes.
Proceedings of the National Academy of Sciences of the United States of America, 109(27), pp. 10903–10908.
https://doi.org/10.1073/pnas.1118641109

Uchida, Y. and Holleran, W.M. (2008).
Omega-O-acylceramide, a lipid essential for mammalian survival.
Journal of Dermatological Science, 51(2), pp. 77–87.
https://doi.org/10.1016/j.jdermsci.2008.01.002

Wilkin, J.K. (1981).
Flushing reactions: consequences and mechanisms.
Annals of Internal Medicine, 95(4), pp. 468–476.
https://doi.org/10.7326/0003-4819-95-4-468

Xu, Y., Luo, J., Guo, X., et al. (2026).
The human skin microbiome is a reflective mirror of alcohol intake.
iMetaMed, 2(1), e70034.
https://doi.org/10.1002/imm3.70034

Yosipovitch, G., Xiong, G.L., Haus, E., et al. (1998).
Time-dependent variations of the skin barrier function in humans: transepidermal water loss, stratum corneum hydration, skin surface pH, and skin temperature.
Journal of Investigative Dermatology, 110(1), pp. 20–23.
https://doi.org/10.1046/j.1523-1747.1998.00069.x

Chapter 11

AlJabr, A., AlAnazi, A.M.I. and AlEtebi, R.A.A. (2026).
Tranexamic acid for hyperpigmentation disorders: a literature review on efficacy and safety in melasma and PIH.
Journal of Cosmetic Dermatology, 25(2), e70692.
https://doi.org/10.1111/jocd.70692

Bala, H.R., Lee, S., Wong, C., et al. (2018).
Oral tranexamic acid for the treatment of melasma: a review.
Dermatologic Surgery, 44(6), pp. 814–825.
https://doi.org/10.1097/DSS.0000000000001518

Bang, J., Im, K., Hwang, Y.-L., et al. (2026).
In vitro and clinical evaluation of the anti-wrinkle efficacy of Medipep-6PN, a novel peptide identified by phage display.
International Journal of Molecular Sciences, 27(4), 1753.
https://doi.org/10.3390/ijms27041753

Burshtein, J., Wei, J., Majewska, L., et al. (2026).
Plant-derived extracellular vesicles in dermatology: a review of emerging therapeutic applications.
Journal of Clinical and Aesthetic Dermatology, 19(2), pp. 15–21.
No DOI available.

Chang, H., Tao, K., Yang, Y., et al. (2025).
Novel cyclized hexapeptide-9 outperforms retinol against skin aging: a randomized, double-blinded, active- and vehicle-controlled clinical trial.
Journal of Cosmetic Dermatology, 24(7), e70290.
https://doi.org/10.1111/jocd.70290

Chang, J.-W., Huang, X., Jiang, W., et al. (2025).
Abrocitinib versus dupilumab: impact on skin barrier function and proteomics in atopic dermatitis.
Journal of the American Academy of Dermatology, 93(2), pp. 406–414.
https://doi.org/10.1016/j.jaad.2025.04.027

Chatzigeorgiou, I., Koumaki, D., Vakirlis, E., et al. (2024).
Restoration of skin barrier abnormalities with IL4/13 inhibitors and JAK inhibitors in atopic dermatitis: a systematic review.
Medicina, 60(8), 1376.
https://doi.org/10.3390/medicina60081376

Choi, Y.L., Park, E.J., Kim, E., et al. (2014).
Dermal stability and in vitro skin permeation of collagen pentapeptides (KTTKS and palmitoyl-KTTKS).
Biomolecules & Therapeutics, 22(4), pp. 321–327.
https://doi.org/10.4062/biomolther.2014.053

Ding, Y., Gao, L., He, L., et al. (2024).
Expert consensus on the clinical application of chemical peels in China (2022).
International Journal of Dermatology and Venereology, 7(4), pp. 249–256.
https://doi.org/10.1097/JD9.0000000000000363

Domaszewska-Szostek, A., Krzyżanowska, M., Polak, A., et al. (2025).
Effectiveness of extracellular vesicle application in skin aging treatment and regeneration: do we have enough evidence from clinical trials?
International Journal of Molecular Sciences, 26(5), 2354.
https://doi.org/10.3390/ijms26052354

Ebrahimi, B. and Naeini, F.F. (2014).
Topical tranexamic acid as a promising treatment for melasma.
Journal of Research in Medical Sciences, 19(8), pp. 753–757.
No DOI available.

Görgens, A., Corso, G., Hagey, D.W., et al. (2022).
Identification of storage conditions stabilizing extracellular vesicles preparations.
Journal of Extracellular Vesicles, 11(6), e12238.
https://doi.org/10.1002/jev2.12238

Grimes, D.R. (2025).
Methodological issues in visible LED therapy dermatological research and reporting.
PLOS ONE, 20(9), e0332995.
https://doi.org/10.1371/journal.pone.0332995

Gupta, J., Gill, H.S., Andrews, S.N., et al. (2011).
Kinetics of skin resealing after insertion of microneedles in human subjects.
Journal of Controlled Release, 154(2), pp. 148–155.
https://doi.org/10.1016/j.jconrel.2011.05.021

Hsieh, M.-C.W., Su, Y.-S., Chen, L.-Y., et al. (2026).
Novel approach for assessment of dermal absorption of extracellular vesicle products using immunoaffinity fluorescent nanodiamonds.
Skin Pharmacology and Physiology, 39(1), pp. 35–46.
https://doi.org/10.1159/000550612

Kim, M.S., Kim, Y.J., Shin, H.J., et al. (2015).
Tranexamic acid diminishes laser-induced melanogenesis.
Annals of Dermatology, 27(3), pp. 250–256.
https://doi.org/10.5021/ad.2015.27.3.250

Kwon, H.H., Yang, S.H., Lee, J., et al. (2020).
Combination treatment with human adipose tissue stem cell-derived exosomes and fractional CO₂ laser for acne scars: a 12-week prospective, double-blind, randomized, split-face study.
Acta Dermato-Venereologica, 100(18), adv00310.
https://doi.org/10.2340/00015555-3666

Li, J., Liu, X., Zhang, Z., et al. (2025).
Efficacy and tolerability of a facial serum before and after ablative fractional carbon dioxide laser: a randomized controlled trial on Chinese women.
Dermatology and Therapy, 15(12), pp. 3561–3575.
https://doi.org/10.1007/s13555-025-01531-x

Maeda, K. and Naganuma, M. (1998).
Topical trans-4-aminomethylcyclohexanecarboxylic acid prevents ultraviolet radiation-induced pigmentation.
Journal of Photochemistry and Photobiology B: Biology, 47(2–3), pp. 136–141.
https://doi.org/10.1016/S1011-1344(98)00212-7

Maghfour, J., Mineroff, J., Ozog, D.M., et al. (2025).
Evidence-based consensus on the clinical application of photobiomodulation.
Journal of the American Academy of Dermatology, 93(2), pp. 429–443.
https://doi.org/10.1016/j.jaad.2025.04.031

Mahmoud, R.H., Peterson, E., Badiavas, E.V., et al. (2025).
Exosomes: a comprehensive review for the practicing dermatologist.
Journal of Clinical and Aesthetic Dermatology, 18(4), pp. 33–40.
No DOI available.

Montero-Vilchez, T., Rodriguez-Pozo, J.-A., Diaz-Calvillo, P., et al. (2022).
Dupilumab improves skin barrier function in adults with atopic dermatitis: a prospective observational study.
Journal of Clinical Medicine, 11(12), 3341.
https://doi.org/10.3390/jcm11123341

Mortazavi, S.M., Moghimi, H. and Maibach, H.I. (2022).
Skin permeability, a dismissed necessity for anti-wrinkle peptide performance.
International Journal of Cosmetic Science, 44(2), pp. 232–248.
https://doi.org/10.1111/ics.12770

Myles, I.A., Earland, N.J., Anderson, E.D., et al. (2018).
First-in-human topical microbiome transplantation with Roseomonas mucosa for atopic dermatitis.
JCI Insight, 3(9), e120608.
https://doi.org/10.1172/jci.insight.120608

Myung, S.-K. and Park, Y. (2025).
Effects of collagen supplements on skin aging: a systematic review and meta-analysis of randomized controlled trials.
The American Journal of Medicine, 138(9), pp. 1264–1277.
https://doi.org/10.1016/j.amjmed.2025.04.034

Nakanishi, S., Kumamoto, J. and Denda, M. (2018).
Tranexamic acid blocks the thrombin-mediated delay of epidermal permeability barrier recovery induced by the cedar pollen allergen, Cry j1.
Scientific Reports, 8(1), 15610.
https://doi.org/10.1038/s41598-018-33898-7

Ngoc, L.T.N., Moon, J.Y. and Lee, Y.C. (2023).
Utilization of light-emitting diodes for skin therapy: systematic review and meta-analysis.
Photodermatology, Photoimmunology & Photomedicine, 39(4), pp. 303–317.
https://doi.org/10.1111/phpp.12841

Nukaly, H.Y., Halawani, I.R., Irtaza, H.M., et al. (2026).
Oral and topical peptides for skin aging: systematic review and meta-analysis of randomized controlled trials.
Frontiers in Medicine, 13, 1618306.
https://doi.org/10.3389/fmed.2026.1618306

Oh, B.H., Hwang, Y.J., Lee, Y.W., et al. (2011).
Skin characteristics after fractional photothermolysis.
Annals of Dermatology, 23(4), pp. 448–454.
https://doi.org/10.5021/ad.2011.23.4.448

Prajapati, S.K., Lekkala, L., Yadav, D., et al. (2025).
Microbiome and postbiotics in skin health.
Biomedicines, 13(4), 791.
https://doi.org/10.3390/biomedicines13040791

Robinson, L.R., Fitzgerald, N.C., Doughty, D.G., et al. (2005).
Topical palmitoyl pentapeptide provides improvement in photoaged human facial skin.
International Journal of Cosmetic Science, 27(3), pp. 155–160.
https://doi.org/10.1111/j.1467-2494.2005.00261.x

Sasaki, G.H. (2019).
The significance of trans-epidermal water loss after microneedling and microneedling-radiofrequency procedures: Histological and IRB-approved safety study.
Aesthetic Surgery Journal Open Forum, 1(3), ojz017.
https://doi.org/10.1093/asjof/ojz017

Wang, H., Yang, F., Wang, H., et al. (2024).
Effect of CO₂ fractional laser combined with recombinant human epidermal growth factor gel on skin barrier.
Medicine (Baltimore), 103(11), e37329.
https://doi.org/10.1097/MD.0000000000037329

Wang, O.J.E., Bajwa, B.B. and Rivers, J.K. (2026).
Exosome-based therapies in dermatology: a scoping review.
Journal of Drugs in Dermatology, 25(4), pp. 368–376.
https://doi.org/10.36849/jdd.9610

Welsh, J.A., Goberdhan, D.C.I., O’Driscoll, L., et al. (2024).
Minimal information for studies of extracellular vesicles (MISEV2023): from basic to advanced approaches.
Journal of Extracellular Vesicles, 13(2), e12404.
https://doi.org/10.1002/jev2.12404

Woo, Y.R. and Kim, H.J. (2024).
Interaction between the microbiota and the skin barrier in aging skin: a comprehensive review.
Frontiers in Physiology, 15, 1322205.
https://doi.org/10.3389/fphys.2024.1322205

Xu, Z., Yu, B., Xu, B., et al. (2024).
Oral tranexamic acid treats papulopustular rosacea by improving the skin barrier.
Journal of Cosmetic Dermatology, 23(9), pp. 2918–2926.
https://doi.org/10.1111/jocd.16339

Yuan, C., Wang, X.M., Yang, L.J., et al. (2014).
Tranexamic acid accelerates skin barrier recovery and upregulates occludin in damaged skin.
International Journal of Dermatology, 53(8), pp. 959–965.
https://doi.org/10.1111/ijd.12099

Zhang, B., Lai, R.C., Sim, W.K., et al. (2024).
An assessment of administration route on MSC-sEV therapeutic efficacy.
Biomolecules, 14(6), 622.
https://doi.org/10.3390/biom14060622

Zhang, K., Yu, L., Li, F.R., et al. (2020).
Topical application of exosomes derived from human umbilical cord mesenchymal stem cells in combination with sponge spicules for treatment of photoaging.
International Journal of Nanomedicine, 15, pp. 2859–2872.
https://doi.org/10.2147/IJN.S249751

Standards, legislation and regulatory documents

European Parliament and Council of the European Union (2009).
Regulation (EC) No 1223/2009 of the European Parliament and of the Council of 30 November 2009 on cosmetic products (recast).
Official Journal of the European Union, L 342, pp. 59–209.
No DOI available.

International Organization for Standardization (2014).
ISO 17516:2014. Cosmetics — Microbiology — Microbiological limits.
Geneva: International Organization for Standardization.
No DOI available.

U.S. Food and Drug Administration (2019).
Public Safety Notification on Exosome Products.
6 December 2019
No DOI available.

References

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