Is cocamidopropyl betaine a contact allergen? Analysis of network data and short review of the literature.

BACKGROUND: There is no general agreement on whether cocamidopropyl betaine (CAPB) is a skin sensitizer. OBJECTIVE: To examine the evidence for CAPB being a (non-)sensitizer. METHODS: This was a retrospective analysis of data on patch testing with CAPB 1% aqua collected by the Information Network of Departments of Dermatology from 1996 to 2009, with a focus on the patch test reaction profile, and demographic and clinical features of CAPB positives, supplemented by a literature review. RESULTS: Eighty-three thousand eight hundred and sixty-four patients were patch tested with CAPB 1% aqua, yielding 2.16% [95% confidence interval (CI) 2.06-2.26%] positive (2.03% + and 0.13% + + /+ + + ) and 4.6% non-allergic reactions. Thus, the reaction index was-0.368 and the positivity ratio was 94.2%. Reproducibility on synchronous patch testing (n = 6534) was poor [Cohen's kappa: 0.29 (95% CI 0.25-0.32)] and results upon retesting (n = 1157) were almost non-reproducible [kappa: 0.12 (95% CI 0.05-0.19]. Multifactorial logistic regression analysis revealed an increased risk associated with being male and aged ≥40 years, with atopic dermatitis, with scalp dermatitis, with being a hairdresser, and with a 48-hr patch test application. When only + + or + + + reactions were used as a conservative outcome, only the elevated risk in males and in patients with atopic dermatitis remained significant. CONCLUSION: The vast majority of positive reactions to CAPB are presumably false positive. Allergic reactions are very rare. This would support the notion of CAPB being 'not a significant skin sensitizer', in line with current classification systems.

Occupational contact allergy in the building trade in Germany: influence of preventive measures and changing exposure.

PURPOSE: Since 1993, assiduous efforts have been made in Germany to lower the incidence of allergic cement dermatitis by reducing the content of hexavalent chromium (Cr VI). Usage of epoxy resin systems has considerably increased in the building trade in the same period. We analysed data of the Information Network of Departments of Dermatology (IVDK) to evaluate the influence of these changing occupational exposures on frequencies of sensitization. METHODS: IVDK data of 1,153 men working in the building trade (bricklayers, tile setters etc.) presenting with occupational skin disease in the years 1994-2008 were analysed, taking into consideration not only the year of patch testing, but also beginning and duration of work in the building trade. RESULTS: While contact sensitization to chromate decreased from 43.1 to 29.0%, sensitization to epoxy resin increased from 8.4 to 12.4%. Logistic regression analysis revealed that, compared to those who had already worked before 1994, patients having started to work in building trade after 1999 had a significantly decreased risk of chromate sensitization (odds ratio 0.42) and a significantly increased risk of sensitization to epoxy resin (odds ratio 2.79). Additionally, risk of thiuram sensitization increased with the duration of employment. CONCLUSION: Our data confirm that reducing Cr VI content of cement is useful in preventing allergic cement eczema, as previously found in Scandinavia. In contrast, the increasing prevalence of contact sensitization to epoxy resin components in the building trade is alarming. Preventive measures, which have already been implemented, have to be enforced.