Contact allergy to hair-colouring products: a cosmetovigilance follow-up study by four companies in Europe from 2014 to 2017.

Background: A previous analysis of undesirable events (UEvs), reported to four major companies following the use of hair-colouring products in Europe, showed that the reporting rates were stable for both oxidative and direct hair-colouring products over the period 2003-2006.

Objectives: In order to verify the impact of risk management measures implemented since 2006, as well as the impact of a new Commission Regulation (No 1223/2009), the same four companies analysed cosmetovigilance data collected over an additional four-year period (2014-2017). The objective was to determine whether there was any time effect, country effect, or product type effect, as well as identify risk factors.

Allergy Alert Test for p-Phenylenediamine-Allergic Hair Dye Users.

Background: Contact dermatitis to hair dyes remains a health concern. Regulations in many countries require consumer self-testing for hair dyes, but no standardized procedure exists.

Objective: The aim of this study was to develop a self-test protocol for an allergy alert test (AAT) that can elicit a self-noticeable alert signal in p-phenylenediamine (PPD)-allergic consumers.

Skin sensitization quantitative risk assessment for occupational exposure of hairdressers to hair dye ingredients.

Occupational exposure of hairdressers to hair dyes has been associated with the development of allergic contact dermatitis (ACD) involving the hands. p-Phenylenediamine (PPD) and toluene-2,5-diamine (PTD) have been implicated as important occupational contact allergens. To conduct a quantitative risk assessment for the induction of contact sensitization to hair dyes in hairdressers, available data from hand rinsing studies following typical occupational exposure conditions to PPD, PTD and resorcinol were assessed.

Cosmetic efficacy claims in vitro using a three-dimensional human skin model.

A tissue engineered human skin equivalent is successfully used for the testing of raw materials and cosmetic formulations. This reconstructed skin is supported by a collagen-glycosaminoglycan-chitosan biopolymer in which human keratinocytes and dermal fibroblasts were co-cultured to form a tissue that closely reproduces the in vivo architecture of normal human skin and takes into account the complex interactions between epidermis and dermis. On the other hand, dermal and epidermal responses can be assessed separately in the dermal or skin equivalent.

Unveiling the molecular basis of intrinsic skin aging(1).

The process of skin aging is a combination of an extrinsic and intrinsic aspect, and knowing the molecular changes underlying both is a prerequisite to being able to effectively counter it. However, despite its importance for a deeper understanding of skin aging as a whole, the process of intrinsic skin aging in particular has barely been investigated. In this study, the molecular changes of intrinsic skin aging were analyzed by applying 'Serial Analysis of Gene Expression' (SAGE(TM)) to skin biopsies of young and aged donors.