pH in nature, humans and skin.

Area of Science:

• Dermatology and skin physiology.
• Biochemistry of epidermal enzymes.
• Microbiology of skin microbiota.

Background:

• The stratum corneum's physiological pH (4.1-5.8) is crucial for skin health.
• Mechanisms maintaining skin pH include filaggrin degradation and ion exchange.
• Acidic skin pH historically viewed as an antimicrobial barrier, now known to influence multiple skin functions.

Purpose of the Study:

• To explore the multifaceted role of skin pH in epidermal homeostasis.
• To investigate the impact of pH on skin barrier function, lipid metabolism, and cellular processes.
• To understand the link between altered skin pH and various dermatological conditions.

Main Methods:

• Review of existing literature on skin pH physiology and regulation.
• Analysis of enzyme activity and skin barrier function in relation to pH.
• Examination of pH changes in disrupted skin barriers and disease states.

Main Results:

• Skin pH regulates enzymes vital for ceramide metabolism and epidermal differentiation.
• Disruption of the skin barrier leads to elevated pH.
• Increased skin pH is observed in inflammatory skin diseases like atopic dermatitis, acne, and rosacea, as well as in aged and dry skin.

Conclusions:

• Restoring physiological skin pH through acidification can normalize skin microbiota.
• Topical treatments that acidify the skin promote barrier repair and epidermal differentiation.
• Managing skin pH is a key therapeutic strategy for improving skin health and treating inflammatory skin conditions.