Hair dye and risk of skin sensitization induction: a product survey and quantitative risk assessment for para-phenylenediamine (PPD)

Toxic Ingredients in Personal Care Products: A Dermatological Perspective

Environmental dermatology is the study of how environmental factors affect the integumentary system. The environment includes natural and built habitats, encompassing ambient exposure, occupational exposures, and lifestyle exposures secondary to dietary and personal care choices. This review explores common toxins found in personal care products and packaging, such as bisphenols, parabens, phthalates, per- and poly-fluoroalkyl substances, p-phenylenediamine, and formaldehyde. Exposure to these toxins has been associated with carcinogenic, obesogenic, or proinflammatory effects that can potentiate disease. In addition, these compounds have been implicated as endocrine-disrupting chemicals that can worsen dermatological conditions such as acne vulgaris, or dermatitis. Certain pollutants found in personal care products are not biodegradable and have the potential to bioaccumulate in humans. Therefore, even short-term exposure can cause long-lasting issues for communities. The skin is often the first point of contact for environmental exposures and serves as the conduit between environmental toxins and the human body. Therefore, it is important for dermatologists to understand common pollutants and their acute, subacute, and chronic impact on dermatological conditions to better diagnose and manage disease.

Considering the risk of a coloring shampoo with the function of gray hair cover cosmetology and skin barrier: A systematic review

Background and Aims

As the number of demanders who want to easily cover gray hair increases, the demand market is rapidly expanding along with the demand for coloring shampoos that can be dyed while shampooing. Among these coloring shampoo ingredients, it is necessary to differentiate products that are safe and harmless to the human body in consideration of hair loss or skin barrier problems caused by trihydroxybenzene (THB) ingredients. The correct selection criteria were presented by examining the problems, effectiveness, and side effects when used in relation to the skin barrier through previous studies by consideration of the ingredients of the coloring shampoo and the skin barrier of the scalp.

Methods

The analysis of this study looked at previous studies through a systematic literature review through related keywords for coloring shampoo. After reviewing 150-200 related prior papers, a total of 39 review papers were finally selected using the PRISMA flow diagram.

Results

It was confirmed through a literature review that the coloring shampoo containing THB, which is harmful to the human body, has a detrimental effect on the scalp-skin barrier.

Conclusion

This study examined the harmfulness of coloring shampoo on the scalp skin barrier. It was confirmed that frequent coloring shampoo procedures can have various harmful effects on the scalp. Therefore, it is important to reduce side effects caused by the use of harmful ingredients and maintain a healthy scalp condition through analysis of sufficient scalp conditions and consultation with experts. In addition, various studies on the standard standards and age for harmful ingredients are suggested.

Dermal exposure and hair dye: Assessing potential bladder cancer risk from permanent hair dye

Hair dye products include a range of chemicals, depending on the type and color. A common primary intermediate compound used to achieve the permanent effect of hair dye is para-phenylenediamine (PPD). 4-aminobiphenyl (4-ABP) has reportedly been found as a trace contaminant (presumably from the para-phenylenediamine [PPD] ingredient) in consumer permanent hair dye. While several regulatory agencies have designated 4-ABP as a human bladder carcinogen based on evidence in humans and experimental animals, only the Office of Environmental Health Hazard Assessment (OEHHA) have established a cancer risk value for 4-ABP of 0.03 μg/day based on liver tumors developed in mice. A hypothetical dermal risk assessment was performed to estimate the bladder cancer risk associated with exposure to 4-ABP from personal use of permanent hair dye potentially containing incidental 4-ABP. Previously published laboratory analyses characterizing 4-ABP concentrations in consumer hair dyes indicate the concentrations can range from below the limit of detection to 8120 ppb. Precautionary estimates of human scalp surface area, maximum skin adherence, hair dye retention factor, and percent dermal absorption were used to estimate the daily systemic exposure doses (SEDs) from dermal application of hair dye. The estimated SEDs ranged from 0.05 to 3000 pg/day. A margin of safety (MOS) was calculated as the ratio of the NSRL to the SED and ranged from 10 to 570,000. The results of this study suggest that there is no indication of increased risk of bladder cancer in humans from exposure to 4-ABP in consumer hair dye, especially as it is extremely unlikely that a consumer would use permanent hair dye on a daily basis (as this assessment models).

Hair Dye Ingredients and Potential Health Risks from Exposure to Hair Dyeing

Given the worldwide popularity of hair dyeing, there is an urgent need to understand the toxicities and risks associated with exposure to chemicals found in hair dye formulations. Hair dyes are categorized as oxidative and nonoxidative in terms of their chemical composition and ingredients. For several decades, the expert panel's Cosmetic Ingredient Review (CIR) has assessed the safety of many of the chemicals used in hair dyes; however, a comprehensive review of hair dye ingredients and the risk of exposure to hair dyeing has not been documented. Herein, we review the safety of the various chemicals in oxidative and nonoxidative hair dyes, toxicities associated with hair dyeing, and the carcinogenic risks related to hair dyeing. While many compounds are considered safe for users at the concentrations in hair dyes, there are conflicting data about a large number of hair dye formulations. The CIR expert panel has ratified a number of coloring ingredients for hair dyes and banned a series of chemicals as carcinogenic to animals and unsafe for this application. The use of these chemicals as raw materials for producing hair dyes may result in the synthesis of other contaminants with potential toxicities and increased risk of carcinogenesis. It is an open question whether personal or occupational hair dyeing increases the risk of cancer; however, in specific subpopulations, a positive association between hair dye use and cancer occurrence has been reported. To address this question, a better understanding of the chemical and mechanistic basis of the reported toxicities of hair dye mixtures and individual hair dye ingredients is needed. It is anticipated that in-depth chemical and systems toxicology studies harnessing modern and emerging techniques can shed light on this public health concern in the future.

Combinative ex vivo studies and in silico models ProTox-II for investigating the toxicity of chemicals used mainly in cosmetic products

Human data on remains sparse and of varying quality and reproducibility. Ex vivo experiments and animal experiments currently is the most preferred way to predict the skin sensitization approved by the regulatory agencies across the world. However, there is a constant need and demand to reduce animal experiments and provide the scope of alternative methods to animal testing. In this study, we have compared the predictive performance of the published computational tools such as ProTox-II, SuperCYPsPred with the data obtained from ex-vivo experiments. From the results of the retrospective analysis, it can be observed that the computational predictions are in agreement with the experimental results. The computational models used here are generative models based on molecular structures and machine learning algorithms and can be applied also for the prediction of skin sensitization. Besides prediction of the toxicity endpoints, the models can also provide deeper insights into the molecular mechanisms and adverse outcome pathways (AOPs) associated with the chemicals used in cosmetic products.