CD01 Sodium benzoate: an important allergen to patch test to — is 5% in petrolatum too irritant?

Abstract Sodium benzoate is a naturally occurring preservative present in substances including cinnamon and apples. It used as food increasingly leave-on wash-off personal care products (PCPs), moisturizers, hand washes, shampoos, mouthwash, toothpaste baby wipes. Increased use results, part, from European Union legislation regulating other preservatives, notably methylchloroisothiazolinone methylisothiazolinone, which are banned PCPs required to be reduced concentrations products. was recently recommended for consideration inclusion the British Society Cutaneous Allergy facial series after national audit demonstrated that 1.5% of patients tested positive on patch testing when sodium 5% petrolatum (pet.) (Rolls S, Owen E, Bertram CG et al. What in? out? Updating series. Br J Dermatol 2021; 184:151–5). In our institution, 3229 were pet. Chemotechnique Diagnostics™ 2008 2022. targeted series, bakery cheilitis (2008–2022), variably fragrance (2012–2018) cosmetic (2015–2018 2021–2022) We noted many irritant reactions undertook an audit. Fifty-seven (1.8%) had (+/++), 52 (1.6%) doubtful (? +), 133 (4.1%) reactions. Of reactions, 38 (66.7%) current relevance 19 (33.3%) unknown relevance. The frequency (+/++) different follows: 1.5%, 1.7% 2.1%. Concerningly, over three times more or (5.7%) than those who (1.8%). When test preparation decreased, rate irritancy usually also decreases (Johansen J, Aalto-Korte K, Agner T Contact Dermatitis guideline diagnostic – recommendations best practice. 2015; 73:195–221). Given known allergen with increasing use, it important optimum concentration vehicle ensure adequate sensitivity but low irritancy. Decreasing 2% pet., commercially available, may reduce risk false positives. recommend dilutional studies should performed comparing hope latter comparatively nonirritant without loss sensitivity.