The Behind-the-Knee test: an efficient model for evaluating mechanical and chemical irritation

A systematic review of allergic and irritant contact dermatitis of the vulva: The most important allergens/irritants and the role of patch testing

Vulvar allergic contact dermatitis (vACD) and irritant contact dermatitis (vICD) are common and accompanied by a great burden on the patient's life. We aimed to review the existing literature on vACD and vICD in order to provide a comprehensive reference list of potential vulvar allergens and irritants, as well as to establish the role of patch testing therein. A systematic search was performed in Medline, Embase and Web of Science using a search string based on the PICO-format. The study protocol was registered at PROSPERO (CRD42021239527). Multiple allergens were identified and included metals, topical drugs, fragrances, preservatives, cosmetic constituents and rubber components. Not all positive reactions were, however, considered to be relevant. Patch testing is the primary tool for the identification of the causal allergens. Testing with standard series alone was proven to be insufficient. Little information about irritants was found. In the future, additional series and late readings should be considered in standard practice. Studies on vICD are scarce and further research is necessary. More population-based research should be performed.

A Feminine Care Clinical Research Program Transforms Women's Lives

Feminine hygiene products and menstruation education have transformed the lives of women throughout the world. The P&G Feminine Care Clinical Innovation Research Program has played a key role by expanding scientific knowledge as well as developing technical insights and tools for the development of feminine hygiene products. The aim has been to meet the needs of women throughout their life stages, advancing their urogenital health beyond just menstruation, as well as helping to understand the role of sex hormones in various important health issues that women face. This review article highlights key contributions and research findings in female hygiene products, urogenital health research, and method development. The clinical research team focused on utilizing the results of clinical safety studies to advance the acceptance of feminine hygiene products world-wide. Key findings include that perception of skin sensitivity is not limited to the facial area, but is also relevant to the body and the genital area. Also, they shed light on the role of estrogen in autoimmune diseases as well as premenstrual syndrome. Efforts in the method development area focused on innovative tools that are reliable, predictive of clinical trial results and capable of measuring wear comfort, genital skin health, and the impact of product use on the consumer’s quality of life. A novel method, behind-the-knee (BTK) test, developed to model irritation under normal wear conditions, was the first to account for both chemical and mechanical sources of irritation. The method has been accepted by the FDA as a substitute in clinical trials in some cases, and by American Society for Testing and Materials as a global standard test method. Additional proprietary methods were developed to enhance visual grading of irritation using cross-polarized light, to measure the amount of lotion transferred from sanitary pads, and to evaluate the skin mildness. Finally, the Farage Quality of Life tool was created to measure consumer’s well-being. Based on the results of this extensive clinical research and the newly developed testing methods, the changing needs of women throughout their life stages are better met.

Sensitive skin: an overview

Sensitive skin is a condition of subjective cutaneous hyper-reactivity to environmental factors. Subjects experiencing this condition report exaggerated reactions when their skin is in contact with cosmetics, soaps and sun screens, and they often report worsening after exposure to dry and cold climate. Although no sign of irritation is commonly detected, itching, burning, stinging and a tight sensation are constantly present. Generally substances that are not commonly considered irritants are involved in this abnormal response.Sensitive skin and subjective irritation are widespread but still far from being completely defined and understood. A correlation between sensitive skin and constitutional anomalies and/or other triggering factors such as occupational skin diseases or chronic exposure to irritants has been hypothesized. Recent findings suggest that higher sensitivity can be due to different mechanisms. Hyper-reactors may have a thinner stratum corneum with a reduced corneocyte area causing a higher transcutaneous penetration of water-soluble chemicals. Alterations in vanilloid receptors and changes in neuronal transmission have been described. Monitoring skin parameters such as barrier function, proclivity to irritation, corneocyte size and sensorial transmission can also be useful to identify regional differences in skin sensitivity.

Dermatological testing of an improved apertured film surface for feminine hygiene pads

CONTEXT

Apertured polyethylene films (AF) have been used as a surface for sanitary pads for decades because they are compatible with the skin and keep the pad surface drier. A modified film (AF-plus) with improved fluid handling and a smoother, suppler texture has been developed. We hypothesized that these changes would improve both performance and skin compatibility. However, distinguishing the skin effects of materials that are inherently mild is a challenge.

OBJECTIVES

(i) To compare the skin irritation potential of pads with AF-plus modified film relative to the standard AF film and (ii) to assess the potential for the AF-plus film to induce delayed contact hypersensitivity.

MATERIALS AND METHODS

Pads bearing the AF-plus film were compared to pads with the standard AF film in a behind-the-knee (BTK) test, which assesses the combination of chemical irritation and frictional effects of materials applied to the popliteal fossa under a semi-occlusive bandage. Erythema on the skin surface was scored with the naked eye and subsurface tissue erythema was visualized and scored using cross-polarized illumination. Skin dryness was scored with the naked eye only. One-sided statistical evaluations were performed to test the hypothesis of AF-plus film superiority. The potential of the AF-plus film to induce delayed contact hypersensitivity was assessed by a human repeat insult patch test (HRIPT).

RESULTS

Pads with the AF-plus surface were significantly milder to skin in the BTK test, producing lower levels of both surface and subsurface tissue erythema. Moreover, subjects with preexisting erythema on the skin surface at study start developed comparatively less erythema over the course of the study overall with the AF-plus pad compared to the AF pad. No significant difference in skin dryness was observed between product groups. The AF-plus pad showed no evidence of inducing delayed contact hypersensitivity.

CONCLUSIONS

The AF-plus pad was superior to the AF pad in terms of skin mildness as discerned by objectively scored surface and subsurface tissue erythema. In subjects with preexisting erythema, the AF-plus pad appeared to contribute less to the further development of inflammation under the test conditions. Given the compositional similarities in the two films, the results could point to more limited contribution of the AF-plus film to skin friction, one of the factors simulated by the BTK test protocol.

Évolution des couches à usage unique et amélioration de l'état cutané des du siège enfants

Keeping babies skin dry in the diaper environment, reducing leaking while increasing absorbency and preventing skin pH increase lead to provide better skin tolerance disposable diapers. During 80's, basic cellulose diapers were replaced by the introduction of absorbent gelling materials (AGM) and since 90's by microbreatheable diapers. These advances in diaper technology have contributed to the reduction of diaper dermatitis.

Influence of usage practices, ethnicity and climate on the skin compatibility of sanitary pads

Modern disposable sanitary pads are becoming available worldwide. Regional differences in usage practices, ethnicity, and climate may influence their skin compatibility. Pad usage practices depend on culture, economics, and menstrual physiology. Daily usage is higher in Japan and but lower in Nigeria compared to North America or Western Europe. Evidence for ethnic differences in skin irritant susceptibility is not compelling. Dark skin may be less susceptible to certain irritants than fair skin; the Japanese may experience a higher degree of sensory irritation than Caucasians. Ambient conditions such as high temperature and humidity increase the skin temperature and skin surface moisture under sanitary pads by small but measurable amounts, causing no discernible skin irritation; vapor-permeable pad backings reduce these effects. Cold dry conditions, which can irritate exposed skin, may not affect vulvar skin to the same degree due to its elevated hydration and occlusion. To address the practical significance of these variables, results of prospective clinical trials of sanitary pads performed by industry and academic scientists in North America (Indiana), Mexico, Western Europe (Munich, Athens, Goteborg, Sweden), Eastern Europe (Kiev) and Africa (Abuja, Nigeria) were reviewed. Despite the diverse range of conditions, no significant adverse skin effects were observed with modern pads compared to traditional pad designs. Study participants generally preferred modern pads for performance and comfort.