Tolerability of hair cleansing conditioners: a double-blind randomized, controlled trial designed to evaluate consumer complaints to the U.S. Food and Drug Administration

Evaluating the Impact of Hair Care Product Exposure on Hair Follicle and Scalp Health

Human hair follicles traverse the epidermis and dermis, and are comprised of specialised cells including dermal papilla cells (DPCs). DPCs play a critical role in the development and growth of both hair and follicle structure. While exposure of DPCs to undiluted exogenous compounds is unlikely, exposure to diluted compounds is possible should dermal penetration occur. The goal of this study was to evaluate the impact on hair and scalp health following application of a hair care product. Due to the lack of standardised and validated test systems for evaluating hair follicle health, the HairSkin® model, which uses intact human scalp samples, was adapted to evaluate hair follicle and scalp health. Similarly, the Franz diffusion cell assay and matrix-assisted laser desorption ionisation-Fourier transform ion cyclotron resonance (MALDI-FTICR) were adapted to evaluate dermal penetration. The results of this study demonstrate that application of the hair care product does not result in appreciable dermal penetration, suggesting that DPCs are unlikely to be exposed to undiluted product. Additionally, hair follicle health was not impacted following product application. While this study is exploratory, these results suggest that the combination of test systems utilised herein provides valuable insight and warrants further development and validation.

Contact Dermatitis Associated With Hair Care Products: A Retrospective Analysis of the North American Contact Dermatitis Group Data, 2001-2016

BACKGROUND

Hair care products (HCPs) may cause both allergic contact dermatitis (ACD) and irritant contact dermatitis (ICD).

OBJECTIVES

The aims of the study were to determine the prevalence of HCP-associated ICD/ACD and to characterize relevant allergens.

METHODS

This study is a retrospective analysis of North American Contact Dermatitis Group (NACDG) patch test data, 2001-2016.

RESULTS

Of 38,775 patients tested, 3481 (9.0%) had positive patch test reactions associated with HCPs. The HCP-positive patients were significantly more likely to be female (79.9% vs 66.0%) and/or have primary sites of dermatitis on the face (32.0% vs 27.8%) or scalp (15.4% vs 2.2%) compared with the HCP-negative patients (P < 0.0001). Of 4908 HCP-associated positive patch test reactions, 86.9% (n = 4263) were due to allergens on the NACDG screening series; p-phenylenediamine (35.8%), methylisothiazolinone (9.7%), methylchloroisothiazolinone/methylisothiazolinone (8.7%), and cocamidopropyl betaine (5.9%) were the most frequent. Most reactions (87.7%, 3736/4263) were currently clinically relevant. The most common job associated with 366 occupationally related NACDG HCP-associated allergens was hairdresser/cosmetologist (71.9%). Two hundred eighty-two patients (0.7%) had ICD associated with HCPs. Shampoo/conditioners were the most frequent source of NACDG HCP-associated reactions (47.3%) and HCP-associated ICD (45.0%).

CONCLUSIONS

Of the HCP-positive patients, 18.5% had HCP reactions to allergens not on the NACDG screening series, underscoring the importance of patch testing to expanded series in patients suspected of HCP allergy.

An in vitro human assay for evaluating immunogenic and sensitization potential of a personal care and cosmetic product

With the reduction or elimination of animal testing, manufacturers are left with limited options, as few robust in vitro tests are available and human studies are costly. Recently, concerns have been raised regarding potential adverse health effects associated with use of WEN by Chaz Dean (WCD) cleansing conditioners. The purpose of this study was to evaluate the immunogenic potential of a WCD hair cleansing conditioner by utilizing a novel in vitro human skin explant test. Peripheral blood mononuclear cells (PBMCs) and human skin biopsies were obtained from healthy volunteers. Monocyte derived dendritic cells (MoDCs) were generated, primed by 0.01% WCD cleansing conditioner exposure for 24 h, co-cultured with autologous lymphocytes for 4 days, and then cultured with skin biopsies for 3 days. The skin biopsies then underwent histopathological evaluation, and T cell proliferation and IFNγ levels were determined. Overall, this study showed that treatment with 0.01% WCD cleansing conditioner resulted in a negative prediction for in vivo immune response. Further, this analysis shows that the skin explant test is a viable alternative to animal testing for complex mixtures or commercially available products.

Devising a Tier-based Skin Sensitisation Screening Strategy for Personal Care and Cosmetic Products

Concerns regarding the use of potential skin sensitisers in personal care and cosmetic products continue to grow. The goal of this study was to develop a proof-of-concept tier-based screening strategy for the assessment of skin sensitisation potential by using non-animal methodologies. As a case example, this screening framework was applied to three WEN® by Chaz Dean cleansing conditioners. The first tier of testing utilised the Organisation for Economic Co-operation and Development (OECD) Quantitative Structure Activity Relationship Toolbox profiler to evaluate the skin sensitisation potential of individual ingredients within the formulation; a literature review was performed on the substances that generated in silico alerts. Tier 2 testing utilised the OECD in chemico Test Guideline (TG) 442C to evaluate these substances. Tier 3 testing adapted OECD TG442C to evaluate the formulated product. The literature review on the four substances that generated in silico alerts revealed that they were not sensitising at the concentrations reported in the formulated products. Tier 2 testing demonstrated that these substances were not sensitising at the concentrations tested. Finally, Tier 3 testing revealed that the evaluated cleansing conditioners had low mean percentage peptide depletion at the concentrations tested. Together, the results obtained suggest that the products tested are unlikely to induce skin sensitisation under the given experimental conditions. These findings are in agreement with other in vitro and clinical studies. The proposed tier-based testing approach may be used as a conceptual framework for the prospective safety screening of other personal care and cosmetic products. However, to establish the validity of the proposed testing strategy, further studies must be performed, including comparisons with established models.