Understanding the formidable nail barrier: A review of the nail microstructure, composition and diseases.

The topical treatment of nail fungal infections has been a focal point of nail research in the past few decades as it offers a much safer and focused alternative to conventional oral therapy. Although the current focus remains on exploring the ways of enhancing permeation through the formidable nail barrier, the understanding of the nail microstructure and composition is far from complete. This article reviews our current understanding of the nail microstructure, composition and diseases. A few of the parameters affecting the nail permeability and potential causes of the recurrence of fungal nail infection are also discussed.

Stratum corneum cytokines, structural proteins, and transepidermal water loss: effect of hand hygiene.

BACKGROUND/AIMS: There are few reports on the cytokine response to high frequency hand hygiene among health care workers (HCWs) in an occupational setting. We have observed significant skin barrier compromise consistent with chronic irritant contact dermatitis in HCWs. We hypothesized that repetitive hand hygiene would activate the epidermal inflammatory cascade and lead to changes in structural proteins and cytokines. METHODS: Keratin 6, keratin 1, 10, 11, involucrin, IL1alpha, TNFalpha, IL8, IL1RA, and IL10 were analyzed from the SC using bead-based arrays. Knuckle and dorsum samples were evaluated for HCWs (n=23) before and after repetitive hand hygiene and compared with those of age-matched non-wet workers (n=23) without hand skin irritation. Erythema, dryness, and barrier integrity were measured. RESULTS: Transepidermal water loss (TEWL) was higher for HCWs but unchanged with exposure. IL1alpha and TNFalpha were highest in control volar forearm. IL1alpha, TNFalpha, and IL8 were significantly lower in HCWs than controls despite higher erythema, dryness, and TEWL. Decreases in keratin 1, 10, 11, increases in keratin 6, and reduction in IL1alpha, TNFalpha, and IL8 were seen after hand hygiene. CONCLUSION: This preliminary study showed significantly lower SC biomarker levels in HCW compared with controls and regional differences between the hand and forearm. Exposure to repetitive hand hygiene results in substantial chronic skin irritation without time for barrier recovery between work periods. The impact on SC structural proteins and cytokines has many commonalities with chronic inflammation, although mechanistic questions remain.

Natural moisturizing factors (NMF) in the stratum corneum (SC). I. Effects of lipid extraction and soaking.

Natural moisturizing factor (NMF) is essential for appropriate stratum corneum hydration, barrier homeostasis, desquamation, and plasticity. It is formed from filaggrin proteolysis to small, hygroscopic molecules including amino acids. We hypothesized that common lipid extraction and soaking in water would alter the level of NMF in the upper SC and its biophysical properties. A novel method of measuring and quantifying the amino acid components of NMF is presented. Adhesive tapes were used to collect samples of the stratum corneum (SC) and were extracted with 6mM perchloric acid for analysis by reverse-phase HPLC. HPLC results were standardized to the amount of protein removed by the tapes. An increase in NMF was found with increased SC depth. Also, the combination of extraction and soaking was found to increase NMF loss relative to control or to extraction or soaking alone. Our results indicate that common skin care practices significantly influence the water binding materials in the upper SC. The findings have implications for the evaluation and formulation of skin care products.

Natural moisturizing factors (NMF) in the stratum corneum (SC). II. Regeneration of NMF over time after soaking.

The detrimental effects of prolonged water exposure on skin are well known. Information on the effects of short-term exposure, e.g., during bathing, showering, and hand washing, on NMF levels is limited. In an attempt to isolate the effects of soaking on the NMF, a time course for skin sample collection was devised in which adhesive tapes were applied 0.5 and four hours after soaking of the treated arm. Significant decreases in NMF levels, quantified by HPLC analysis of serial tape strips, were observed 0.5 hours after soaking, with a replacement of NMF occurring by the four-hour mark. This replacement corresponds to a parallel rebound in skin pH also observed at these times. Stratum corneum hydration values, measured instrumentally as the rate of moisture accumulation (MAT), however, were depressed 0.5 hours post-soaking and remained low four hours later. In addition, significant increases in skin pH were observed during the immediate post-soak period. These findings suggest that short-term exposure to water alone produces significant changes in the stratum corneum.

Effect of topical treatments on irritant hand dermatitis in health care workers.

BACKGROUND: Irritant contact dermatitis (ICD) from repetitive hand hygiene is the primary reason for compliance failure among health care workers (HCWs). Chronic ICD has implications for infection control because higher bacterial counts are associated with increased skin compromise. Guidelines recommend lotions/creams to lessen irritation. We evaluated the effects of 5 to 10 daily applications of a test cream (A, glove and chlorhexidine gluconate compatible) and current lotions/creams (B) compared with a control of normal skin care. METHODS: Outcomes were visual skin erythema and dryness, excess erythema (quantitative image analysis), and hydration among 80 HCWs in an intensive care unit. RESULTS: Knuckle dryness was lower for both treatments than the no treatment control (P < .02) after 2 weeks. Skin treated with A had lower knuckle erythema (P=.03) than B and control. HCWs using A had lower excess erythema (right) than B and control (P < .04). Excess erythema was lower for A and B versus control (P=.003). CONCLUSION: Reduction in erythema suggests that frequent use of cream A may mitigate the damaging effects of repetitive hand hygiene and allow the skin to recover. Intensive treatment of HCW ICD may be required to counteract the skin compromise and minimize the negative impact on infection control.

Use of digital photography and image analysis techniques to quantify erythema in health care workers.

BACKGROUND/AIMS: Nosocomial infections affect up to 26% of ICU patients. Compliance with the required hand hygiene procedures remains low, rarely exceeding 50%, with skin irritation as one of the main reasons for lack of conformity. The aim was to quantify the epidermal barrier effects, particularly erythema, from repetitive exposure to hand hygiene procedures among health care workers (HCWs) using an objective, reliable clinical method that could evaluate the entire hand surface. METHODS: The hand skin of HCWs was evaluated before the initial scrub and at the end of multiple 2-3 days work cycles during spring (n=54) and winter (n=60) trials. The skin condition was measured with live visual skin evaluation (LSG), digital image analysis (DIA) of high-resolution digital images, and visual perception evaluation (VPS) of image pairs. RESULTS: The HCWs had significantly higher values of erythema than the non-HCW control group with all methods. Knuckle erythema increased over the cycle in both seasons. It decreased during recovery in spring and continued to increase during recovery in winter. For the DIA area of excess redness, the quantitative measure of erythema, the decrease over the cycle in spring was significantly different than the increase over the cycle in winter. Minimal changes in area of excess redness occurred during recovery in both seasons. With the VPS, both judges found a decrease in erythema during recovery in spring and an increase during recovery in winter, indicating significant differences for spring vs. winter (P<0.05). No differences in VPS erythema were seen for either product set over the work cycle during spring. Correlations were observed for (1) results for the VPS vs. the LSG method and (2) between excess erythema (mu+sigma) from DIA and the VPS erythema scores. Relatively low correlations were found between the DIA and VPS methods, i.e., knuckle mu+sigma and VPS erythema. CONCLUSIONS: Significant work cycle effects for spring vs. winter were observed with DIA, while significant effects were found during the recovery period with VPS. DIA produced an objective quantitative measure of erythema that was not limited or influenced by other aspects of skin irritation (e.g., dryness, scaling) or texture encountered in the visual methods of LSG and VPS. The DIA method minimizes the difficulty in differentiating erythema severity. Standardization of image capture and processing allows assessment of skin condition across clinical locations. The VPS is a more reliable way to compare skin condition at different times, i.e. beginning vs. the end of a treatment cycle, because images are viewed simultaneously and can be carefully examined for differences.