Ranjit Chatterjee

Changes in Diapered and Nondiapered Infant Skin Over the First Month of Life

Abstract: Time‐ and site‐dependent differences in epidermal barrier properties were investigated over the first 28 days of life in healthy term newborn infants. Diapered and nondiapered skin sites were contrasted to the volar forearm of adults (mothers). Thirty‐one term infants were evaluated in the hospital on postnatal day 1 and at home on days 4, 7, 14, 21, and 28 for a total of six visits. Measurements included baseline skin hydration, continuous capacitive reactance, peak water sorption, rate of water desorption, skin pH, skin temperature, and environmental conditions. Changes in epidermal barrier properties over the first 4 weeks of life included an increase in surface hydration, a decrease in transepidermal water movement under occlusion, a decrease in surface water desorption rate, and a decrease in surface pH. Diapered and nondiapered regions were indistinguishable at birth but exhibited differential behavior over the first 14 days, with the diapered region showing a higher pH and increased hydration. Maternal measurements remained constant throughout the period. We conclude that healthy newborn skin undergoes progressive changes in epidermal barrier properties over the first 28 days. Adult skin testing does not replicate newborn skin during the first month of life.

Chronic ultraviolet radiation-induced increase in skin iron and the photoprotective effect of topically applied iron chelators.

In the skin of albino hairless mice (Skh:HR‐l) there is a basal level of non‐heme iron. Chronic exposure of mice to sub‐erythemal doses of ultraviolet (UV) B radiation results in an increased skin level of non‐heme iron. The iron increase may be the result of a UVB radiation‐induced increase in vascular permeability, which we measured in vivo with the dye marker Evans Blue. We also observed greater non‐heme iron in sun‐exposed vs non‐exposed body sites of human skin, suggesting that similar events occur in man.

Chronic ultraviolet B radiation-induced biochemical changes in the skin of hairless mice.

Abstract— Skh:HR‐l hairless mice were irradiated chronically with sub‐erythemal doses of UVB radiation, and a number of biochemical parameters in the skin were determined after 6,12, 18, and 24 wk of exposure. The parameters measured were water, collagen, elastin, and glycosaminoglycan content; collagenase and elastase levels; and Bz‐Tyr‐OEt (7V‐benzoyl‐L‐tyrosine ethyl ester) and BAPNA (alpha‐N‐benzoyl‐DL‐arginine‐p‐nitroanilide) hydrolyzing activities. Data for UVB radiation‐exposed and chronological age‐matched control mice were compared with respect to unit area and to unit mass of skin. On a unit area of skin basis, UVB radiation exposure increased the level of most parameters. The particular exceptions were collagen and collagenase which remained constant. On a mass of skin basis, though, there is an apparent decrease in collagen content because of the increase in the other skin components. This suggests that there is insufficient collagen in UVB radiation‐exposed skin to support the increasing mass of the tissue.

Development of Diaper Rash in the Newborn

Abstract: Diaper rash is a common infant malady. This study documents the earliest stages of rash in a cohort of 31 healthy term newborns over the first 28 days of life. The diaper area was evaluated using a standardized diaper rash grading scale. The anal, buttock, genital, intertriginous, waistband, and leg areas were assessed separately. At birth the average grade was 0.1 and none of the infants had specific features of advanced rash. Nineteen percent had dryness and/or slight redness. By day 7, 71% of infants had some features of skin compromise, giving rise to an overall grade of 0.6. Both the frequency and overall grade increased during postnatal weeks 2 and 3. Overall scores for days 21 and 28 were the same (1.1). The perianal area had the highest overall regional rash grade. Gender differences were present for the genital area only. These findings indicate that epidermal barrier breakdown is an uncommon finding at birth. Clinical signs of irritated skin in the diaper area develop progressively over the first postnatal month. A better understanding of the mechanisms conferring epidermal barrier protection at birth may be important for developing skin care products and practices to extend this protection later into life.

Biomedical Assessment and Instrumental Evaluation of Healthy Infant Skin

Abstract: The skin forms a critical structural boundary and a perceptual interface for the organism, yet the definition “healthy skin” is surprisingly difficult to describe. The present studys goal was to generate a technical definition of healthy infant skin by quantifying specific biophysical parameters before and after bathing in infants and correlating such parameters to a perceptual maternal evaluation. Fifty‐two healthy infants, 3–6 months old, were evaluated before and after freshwater bathing. Diapered skin had a higher transepidermal water loss (TEWL), surface hydration, moisture accumulation rate (MAT), and friction than nondiapered skin before the bath (p < 0.01). Bathing dramatically altered the biophysical properties at both skin sites, with decreased MAT and lower friction, indicating a drier skin surface (p < 0.01). Visual redness and dryness decreased after bathing (p < 0.01). Blinded grading of optical images showed a significant preference for the skin after bathing (p < 0.01). This study provides the first quantitative technical definition of healthy infant skin with positive correlation to perceptual assessment by independent observers (mothers). The findings support the hypothesis that water binding properties of the stratum corneum are altered by occlusion (diapering) and that bathing introduces acute changes in stratum corneum water interactions, leading to a drier skin surface and a preferred skin appearance.

Hydration vs. skin permeability to nicotinates in man

Background/aims: Prolonged skin occlusion increases stratum corneum water content and often increases skin permeability and irritant dermatitis. As skin wetness from wearing diapers is considered an important factor favouring the onset of diaper dermatitis, optimal diapering might decrease skin hyperhydration and dermatitis. Our aim is to define the quantitative relationship between nicotinate ester (a model penetrant) skin permeability and hydration, as measured by water evaporation rate (WER), decay curves (at individual time points) and WER‐area under the curve (WER‐AUC); and also to determine the level of skin hydration and skin permeability to nicotinates following a diapering simulation.