Elevated Skin pH Is Associated With an Increased Permeability to Synthetic Urine

The Effects of Incontinence Pad Application on Loaded Skin With Reference to Biophysical and Biochemical Parameters: An Exploratory Cohort Study Using a Repeated-Measures Design

PURPOSE

The purpose of this study was to evaluate temporal changes in skin responses following exposure to moisture alone or moisture in combination with mechanical loading.

DESIGN

Comparison cohort with a repeated-measures design.

SUBJECTS AND SETTINGS

The sample comprised 12 healthy volunteers. Participants were purposely sampled from 2 different age groups; half were 32 to 39 years old and half were 50 to 62 years old. Participants identified as White, Black, or mixed; 83% (n = 10) identified as White; 8 (67%) were female.

METHODS

Four sites at the sacrum were challenged with the application of specimens taken from 2 absorbent products; the pad specimens were applied dry or saturated with synthetic urine (SU; pH = 8); a further site from the sacral skin was also selected and used as a control. Skin assessments were performed at different points in time: (1) 60 minutes after exposure to dry or SU-saturated pad specimens; (2) 60 minutes after exposure to pads and mechanical loading (application of pressure in the form of 45°C high sitting); and (3) 30 minutes after removal of all pads (recovery period). Outcome measures were transepidermal water loss (TEWL), stratum corneum (SC) hydration, erythema, pH, and skin inflammatory biomarkers measured at each of the time points described earlier.

RESULTS

The control site and those exposed to dry pads showed minimal time-dependent changes irrespective of the parameter investigated. In contrast, significant increases in TEWL (P = .0000007) and SC hydration responses (P = .0000007) were detected at the sites under absorbent pad specimens after saturation with SU (exposure to moisture). In some participants, TEWL and SC hydration parameters were significantly higher during pressure application. Skin pH remained in the mildly acidic range throughout the test session, and no consistent trends were observed with erythema. Skin inflammatory biomarkers also exhibited considerable variability across participants; none changed significantly over time. Significant differences (P = .02) were also detected following the exposure of moisture in combination with pressure.

CONCLUSION

We evaluated an array of parameters to identify changes following skin exposure to 2 absorbent pads in the presence and absence of SU and mechanical loading. Analysis revealed changes in skin barrier properties in the presence of moisture and/or pressure. This observation suggests a need for frequent pad changing as well as periods of skin off-loading to protect the skin health of individuals with incontinence.

Bacterial invasion into the epidermis of rats with sodium lauryl sulphate-irritated skin increases damage and induces incontinence-associated dermatitis

Incontinence-associated dermatitis (IAD) is caused by prolonged exposure to urine/liquid stool. It is a common and often painful skin condition in older incontinent adults because of poor prevention. Patients with urinary infections are at risk of developing IAD, and to guide the development of novel prevention strategies, we aimed to develop an animal model of IAD by urine and bacteria. First, contralateral sites on the dorsal skin of Sprague-Dawley rats were compromised by sodium lauryl sulphate (SLS), simulating frequent cleansing with soap/water. Filter discs were then placed inside ring-shaped chambers on foam dressings, inoculated with or without Pseudomonas aeruginosa, covered with agarose gels immersed in cultured filtrated urine, and secured in place with an occlusive dressing for 3 days. Untreated and SLS-compromised sites served as controls. The IAD was developed at bacteria-inoculated sites, characterised by severe IAD-like redness that persisted for up to 3 days post-exposure and higher disruption of the skin barrier function compared with non-inoculated sites. Pathological changes included epidermal thickening, partial skin loss, inflammatory cell infiltration, accumulation of red blood cells, and invasion of bacteria into the epidermis. This novel, clinically relevant IAD rat model can serve for future prevention developments.

Moisture-Associated Skin Damage: Expanding and Updating Practice Based on the Newest ICD-10-CM Codes

Moisture-associated skin damage (MASD) occurs when skin is repeatedly exposed to various sources of bodily secretions or effluents, often leading to irritant contact dermatitis with inflammation, with or without denudation of affected skin. In 2020, the Wound, Ostomy and Continence Nurses Society took an initiative that led to the addition of multiple International Classification for Diseases codes for irritant contract dermatitis caused by various forms of MASD for use in the United States (ICD-10-CM). In the last issue of the Journal of Wound, Ostomy and Continence Nursing, a clinical practice alert identifying the various new codes was published that summarized each of the new codes and provided highlights of the descriptions of each of the these codes. This is the first in a series of 2 articles providing a more detailed description of the newest irritant contact dermatitis codes linked to MASD. Specifically, this article reviews the clinical manifestations and assessment, pathophysiology, epidemiology, prevention, and management of irritant contact dermatitis due to saliva, respiratory secretions, and fecal or urinary incontinence.

An exploratory study of the effects of the pH of synthetic urine on skin integrity in healthy participants

Background: Incontinence-associated dermatitis (IAD) develops from prolonged exposure of skin to urine and/or stool and represents a common complication in older adults, reducing the quality of life. Increased pH is an important etiologic factor of IAD, however, the relationship between urinary pH and skin barrier disruption remains unclear. Objective: To examine the effects of synthetic urine (s-urine) at various pH on transepidermal water loss (TEWL), stratum corneum hydration (SCH) and skin surface pH. Methods: S-urine solutions (pH 5.0-9.0) were applied to the volar forearms of 15 healthy participants for 2 hrs, with another site serving as the untreated control. Measurements of TEWL, SCH and skin surface pH were obtained at baseline and after each challenge. Skin buffering capacity was also examined in 5 volunteers by recording skin pH at baseline, after 2 hrs exposure and every 5 mins for 40 mins. Results: TEWL and SCH were increased following exposure to s-urine compared to baseline values. Although there was tendency for pH to an increase after exposure, further investigation showed that changes are only temporal as pH value is restored to baseline within 5 mins. There were no significant differences between solutions. Conclusions: This study revealed that urine disrupts healthy skin integrity; however, its effects are not pH dependent. Transient changes were observed on the acid mantle of the skin due to its innate buffering capacity. Future studies need to examine the effects of urine combined with bacteria responsible for pH elevation in patients with urinary incontinence.

Investigating the release of inflammatory cytokines in a human model of incontinence-associated dermatitis

Incontinence-associated dermatitis (IAD) is a painful complication in elderly patients, leading to reduced quality of life. Despite recent attention, its underlying inflammatory mechanisms remain poorly understood. This study was designed to quantify the release of inflammatory cytokines in a human model of IAD. The left volar forearm of ten healthy volunteers was exposed to synthetic urine and synthetic faeces for 2 h, simulating the effects of urinary and faecal incontinence, respectively, and the subsequent cytokine response compared to that of an untreated control site. Inflammatory cytokines were collected using both the Sebutape® absorption method and dermal microdialysis and quantified using immunoassays. Results from the former demonstrated an upregulation in IL-1α, IL-1RA and TNF-α. Synthetic urine caused a higher median increase in IL-1α from baseline compared to synthetic faeces, whereas synthetic faeces were associated with significantly higher median TNF-α levels compared to synthetic urine (p = 0.01). An increase in IL-1α/IL-1RA ratio was also observed with significant differences evident following exposure to synthetic urine (p = 0.047). Additionally, microdialysis revealed a time-dependent increase in IL-1β and IL-8 following exposure of up to 120 min to synthetic urine and synthetic faeces, respectively. This study demonstrated the suitability of both sampling approaches to recover quantifiable cytokine levels in biofluids for the assessment of skin status following exposure to synthetic fluids associated with incontinence. Findings suggest some differences in the inflammatory mechanisms of IAD, depending on moisture source, and the potential of the cytokines, IL-1α and TNF-α, as responsive markers of early skin damage caused by incontinence.