Role of pH Value in Clinically Relevant Diagnosis

Abstract

As a highly influential physiological factor, pH may be leveraged as a tool to diagnose physiological state. It may be especially suitable for diagnosing and assessing skin structure and wound status. Multiple innovative and elegant smart wound dressings combined with either pH sensors or drug control-released carriers have been extensively studied. Increasing our understanding of the role of pH value in clinically relevant diagnostics should assist clinicians and improve personal health management in the home. In this review, we summarized a number of articles and discussed the role of pH on the skin surface as well as the factors that influence skin pH and pH-relevant skin diseases, but also the relationship of skin pH to the wound healing process, including its influence on the activity of proteases, bacterial enterotoxin, and some antibacterial agents. A great number of papers discussing physiological pH value have been published in recent decades, far too many to be included in this review. Here, we have focused on the impact of pH on wounds and skin with an emphasis on clinically relevant diagnosis toward effective treatment. We have also summarized the differences in skin structure and wound care between adults and infants, noting that infants have fragile skin and poor skin barriers, which makes them more vulnerable to skin damage and compels particular care, especially for wounds.

Keywords: diagnosis; pH value; skin; wound.

Figure 1

The scheme of the skin barrier. Lipid barrier sits atop the acid mantle and displays a pH value of 4–6. Pathogens can be various bacteria. Slight acidic environment is a disadvantage for bacterial colonization.

Figure 2

The schematic structure of (a) epidermis layer, (b) dermis layer, and hypodermis layer.

Figure 3

(a) Course of the pH milieu in acute wounds. (b) Course of the pH milieu in chronic wounds (adapted from [10]).

Figure 4

Assessment of pH-dependent activity profiles of four proteases important in wound healing (adapted from [9]).

Figure 5

Strategies to promote wound healing in newborns/infants (adapted from [102]).