Anne Fuchs

Quantitative risk assessment for skin sensitisation: consideration of a simplified approach for hair dye ingredients.

With the availability of the local lymph node assay, and the ability to evaluate effectively the relative skin sensitizing potency of contact allergens, a model for quantitative-risk-assessment (QRA) has been developed. This QRA process comprises: (a) determination of a no-expected-sensitisation-induction-level (NESIL), (b) incorporation of sensitization-assessment-factors (SAFs) reflecting variations between subjects, product use patterns and matrices, and (c) estimation of consumer-exposure-level (CEL). Based on these elements an acceptable-exposure-level (AEL) can be calculated by dividing the NESIL of the product by individual SAFs. Finally, the AEL is compared with the CEL to judge about risks to human health. We propose a simplified approach to risk assessment of hair dye ingredients by making use of precise experimental product exposure data. This data set provides firmly established dose/unit area concentrations under relevant consumer use conditions referred to as the measured-exposure-level (MEL). For that reason a direct comparison is possible between the NESIL with the MEL as a proof-of-concept quantification of the risk of skin sensitization. This is illustrated here by reference to two specific hair dye ingredients p-phenylenediamine and resorcinol. Comparison of these robust and toxicologically relevant values is therefore considered an improvement versus a hazard-based classification of hair dye ingredients.

Contact allergy to hair colouring products The cosmetovigilance experience of 4 companies (2003-2006)

The post-marketing undesirable events to hair colouring products in the European Union notified to the cosmetovigilance departments of four major cosmetic companies were analysed (2003-2006). The objective was to determine whether there was any time effect (trend to increase or decrease), country effect (significant difference between the countries included in the analysis) or product type effect (direct or oxidation), as well as to identify risk factors. Alleged undesirable events (UEvs, all notifications prior to causality assessment), were compared to the respective undesirable effects (UEfs, reasonably attributable to product use). A detailed analysis was performed on notifications with manifestations compatible with allergic contact dermatitis. No time effect of UEvs and UEfs was shown, for all hair-dye associated notifications and for allergic contact dermatitis, for all hair colouring products together and by product type. The incidence of allergic contact dermatitis to direct hair colouring products was lower for all four companies compared to oxidative hair dyes. The reporting rates of UEfs were statistically higher in the UK for one of four companies. Past history of black henna tattoos appeared as a major risk factor for seriousness of allergic contact reactions.

Hair dye-sensitized hairdressers: the cross-reaction pattern with new generation hair dyes.

Hair dye allergies are a frequent cause of occupational skin disease among hairdressers. Conventional hair dyes contain 4‐phenylenediamine (PPD), 2, 5‐diaminotoluene sulfate (DTS) and 2‐nitro‐4‐phenylenediamine (ONPPD) as allergens. In new generation hair dyes, FD & C and D & C dyes are used in the hair dye formulations. This study investigated the cross‐reaction pattern of new generation hair dyes among hairdressers (n = 40) with a known allergy to PPD and/or DTS and/or ONPPD. In the 40 hairdressers no positive reactions were observed to the single FD & C and D & C dyes. In two hairdressers, doubtful reactions were observed to one or more of the hair dye formulations. The data from this study suggest that for hairdressers sensitized to PPD and/or DTS and/or ONPPD this new generation of hair dyes is a safe alternative for use in their salons.

Reactions of non‐immunologic contact urticaria on scalp, face, and back

This study compared the reactivity of scalp, face, and back to nonimmunologic contact urticants (NICU) to ascertain relative responsiveness.

Human scalp irritation compared to that of the arm and back

Large‐scale data comparing reactions to surfactants between scalp and back and arm are lacking. The sensitivity of responses between scalp and back and arm were explored utilizing an open‐application model for testing the potential irritancy of sodium lauryl sulphate (SLS). 10 bald male Caucasians (mean age 56 ± 9 years) were enrolled. We conducted 5 successive washings: for each wash, the technician pipetted 1 ml of 20% SLS solution into a glass cylinder placed on the designated area with hand pressure that prevented the cylinder leaking. The test area was then rubbed with a Teflon Policeman scrubber for 1 min. Post scrubbing, the solution was absorbed dry with a plastic pipette and blotted by gently applying paper tissues. After a 5‐min rest, the procedure was repeated for 4 more times for a total of 5 times. Skin‐irritancy assessments by visual scoring and instrumental measurements were made at 30 min and 24 h thereafter and squamometry at the end of last washing. Results indicated that most param‐ eters revealed that the back was most sensitive to the SLS challenge. Thus, these data support the current standard skin‐compatibility testing procedure, employing the back for potential irritation testing of hair care products.

Assessment of the Subclinical Irritation of Surfactants: A Screening Open Assay Model

Background: Open application utilizing an exaggerated forearm washing model to determine surfactant subclinical irritant effects has limitations. Objective: A modified screening open model for rapid assessment of surfactant subclinical irritation was used as part of a validation process. Methods: Eight subjects were enrolled and 5 candidate surfactants studied. Sodium lauryl sulfate served as the irritant ‘gold standard’ control. In addition, one site for water washing and one site for normal skin (no treatment) were also included. A technician conducted 3 successive washings with each test surfactant to each volar forearm. Skin irritation and subclinical irritations were assessed with visual scores and bioengineering (transepidermal water loss, skin capacitance and skin color). Squamometry was performed after the last wash. Results: Squamometry provided a sensitive assessment for detecting surfactant-induced subclinical irritation with 3 successive washings in this open assay model. Neither clinical scores nor other biometric methods provided valuable biologic insight. Conclusion: This minimally invasive assay provides a facile and robust means to rank detergent irritant effects in man.

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

ABSTRACT 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. By accounting for wet work, uneven exposure and inter‐individual variability for professionals, daily hand exposure concentrations were derived. Secondly, daily hand exposure was compared with the sensitization induction potency of the individual hair dye defined as the No Expected Sensitization Induction Levels (NESIL). For PPD and PTD hairdresser hand exposure levels were 2.7 and 5.9 fold below the individual NESIL. In contrast, hand exposure to resorcinol was 50 fold below the NESIL. Correspondingly, the risk assessment for PPD and PTD indicates that contact sensitization may occur, when skin protection and skin care are not rigorously applied. We conclude that awareness of health risks associated with occupational exposure to hair dyes, and of the importance of adequate protective measures, should be emphasized more fully during hairdresser education and training. Graphical abstract Figure. No Caption available. HighlightsOccupational Quantitative‐Risk‐Assessment (QRA) approach for the induction of contact allergy to hair dyes in hairdressersQRA uses two independent published sources of hairdresser occupational hand exposure to hair dyesConsidering hand size differences, uneven hand exposure during hair cutting following coloration and wet working conditionsApplication to hair dyes PPD and 2,5‐TDA indicates that sensitization may occur when hand protection is not rigorously used

Necessity for retrospective evaluation of past-positive chemicals in in vitro chromosomal aberration tests using recommended cytotoxicity indices

We have demonstrated that retrospective evaluation of existing data of in vitro chromosomal aberration test using the new cytotoxicity indices RICC (relative increase in cell count) or RPD (relative population doubling) reduces the false-positive rate. We have constructed an algorithm to predict the likelihood that past-positive results would differ when retested accordingly. Here, we emphasize the importance of reviewing existing in vitro chromosomal aberration test results. The present Letter not only supports the rediscovery of potentially useful chemicals excluded from further development as a result of misclassification due to in vitro false-positive results, but also contributes to the development of a precise Quantitative Structure-Activity Relationship (QSAR) model by providing an appropriate training data-set. Furthermore, re-evaluation is expected to provide novel insights into underlying mechanisms and/or key structures involved in the development of chromosomal aberrations.