The Determination of the pH of the Skin of Man and Common Laboratory Animals

Draize, John H.

doi:10.1038/jid.1942.13

Cited by 58 publications

(32 citation statements)

References 5 publications

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“…cheek: pH 5.15 vs. 5.52; legs: pH 5.56 vs. 5.75). In contrast, an early publication from Draize [70] showed hat the average pH on multiple areas was higher in black (pH 5.21) males than in white males (pH 4.85). Thus, it seems that the differences in skin pH seen between different races are related primarily to pigmentation.…”

Section: Factors That Influence Human Surface Phmentioning

confidence: 75%

Stratum corneum pH: Formation and Function of the ‘Acid Mantle’

Fluhr¹,

Elias²

2002

Exog Dermatol

169

112

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Although the acidic surface pH of the skin has been known for over a century, the stratum corneum (SC) pH gradient has been discovered only recently. After removal of SC layers with sequential tape strips, in humans, surface pH starts at 4.5–5.3, increasing by about 2–3 units until it reaches 6.8 in the lower SC. Both exogenous [free fatty acids (FFA) from sebaceous lipid, microbial metabolites, lactic acid from eccrine glands] and endogenous epidermal (enzymatic; membrane antiporters/pumps) mechanisms have been hypothesized to contribute to SC acidification. Three endogenous mechanisms have been identified to date that not only could influence SC pH, but also regulate one or more key SC functions: (1) the histidine-to-urocanic-acid pathway; (2) the phospholipid-to-FFA pathway, and (3) the sodium proton antiporter (NHE1). Additional factors that influence human surface pH have been detected. Endogenous factors, unrelated to pathological features, such as racial differences, topographical variation, gender differences, developmental and age-related changes have been reported. In contrast to adults, human newborn SC displays a near-neutral surface pH, which declines rapidly over the first postnatal month. Furthermore, endogenous factors have been described, as in atopic dermatitis, seborrheic dermatitis, diabetes, renal insufficiency and ichthyosis associated with an increased pH. Exogenous factors, like the use of detergents and cleansing products as well as SC hydration, can modify the surface pH. The consequences of SC acidification for several key SC functions are becoming clear, including (1) the role of an acidic pH for SC permeability barrier homeostasis, (2) the pH dependence of extracellular lipid processing and (3) SC integrity/cohesion. Integrity is defined as a measure of resistance to dissociation of adjacent corneocytes by tape stripping (cohesion is a related index defined as the amount of protein removed per stripping). (4) Proteolytic processes leading to desquamation are pH dependent, and (5) an acidic pH provides important antimicrobial resistance.

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Section: Factors That Influence Human Surface Phmentioning

confidence: 75%

Stratum corneum pH: Formation and Function of the ‘Acid Mantle’

Fluhr¹,

Elias²

2002

Exog Dermatol

169

112

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“…That the skin has an acid surface has been recognized for many years (Heuss, 1892;Schade, 1928;Marchionini and Hausknecht, 1938;Blank, 1939;Bernstein and Hermann, 1942;Draize, 1942;Arbenz, 1952;Jolly, 1960). Surprisingly, skin surface pH is neutral at birth in both humans and various animals but with maturation the SC acidifies (Behrendt and Green, 1958;Visscher et al, 2000;Yosipovitch et al, 2000;Behne et al, 2003;Fluhr et al, 2004).…”

Section: Discussionmentioning

confidence: 97%

Functional Consequences of a Neutral pH in Neonatal Rat Stratum Corneum

Fluhr

Man

Brown

et al. 2004

Journal of Investigative Dermatology

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At birth, neonatal stratum corneum (SC) pH is close to neutral but acidifies with maturation, which can be ascribed, in part, to secretory phospholipase A(2) and sodium/hydrogen antiporter 1 (NHE1) activities. Here we assessed the functional consequences of a neutral SC pH in a newborn rat model. While basal transepidermal water loss rates are near normal, barrier recovery (BR) rates after acute barrier disruption were delayed in newborn animals. The abnormality in barrier homeostasis could be improved by topical applications of an acidic buffer, indicating that barrier abnormality is primarily due to high SC pH. The delay in BR correlated with incompletely processed lamellar membranes and decreased activity of beta-glucocerebrosidase. Inhibition of NHE1 delayed BR after acute barrier perturbation. SC integrity was abnormal in newborn animals. Electron microscopy demonstrated decreased corneodesmosomes (CD) in newborn animals with decreased expression of desmoglein 1 and corneodesmosin. Serine protease activation appears to be responsible for CD degradation in newborn animals, because serine protease activity is increased in the SC and it can be reduced by acidification of the SC. The delay in acidification of neonatal SC results in abnormalities in permeability barrier homeostasis and SC integrity and are likely due to pH-induced modulations in enzyme activity.

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“…We did not assess pH distribution in adult rats, because the epidermis becomes very thin and abundant hair follicles make assessment of SC layers by FLIM unreliable. Nevertheless, previous pH electrode measurements on adult rats revealed a pH in the acidic range (Draize, 1942), although somewhat closer to neutral if measured on unshaved skin (Meyer and Neurand, 1991).…”

Section: Acidity Begins In Membrane Domains At the Sc/sg Interface Anmentioning

confidence: 99%