Crystal Zhen Yu Phuan, Wei Liang Koh and Su Ping Regina Lim
Changi General Hospital, Singapore, Singapore
Benzalkonium chloride (BAK) is a cationic quaternary ammonium compound used as an antiseptic and preservative. It is a well‐established irritant and known contact allergen. There are increasing reports of BAK sensitization from detergent and antiseptic exposure, in addition to occupational exposure, antifungals and ophthalmic preparations. Our aim was to identify the prevalence of BAK in locally available cleaning products. Cleaning products were identified online and instore from the largest local supermarket chains and classified into five categories: laundry; dishwashing; household cleaners; disinfectant air freshening; and wet wipes. Each product’s ingredients and respective concentrations were recorded if available. A total of 850 products were studied; 508 (59.8%) with product labels were included in the analysis. Altogether, 176 (34.6%) products contained BAK, while 31 (6.1%) products contained methylisothiazolinone and methylchloroisothiazolinone as an active ingredient. Among products containing BAK, 86 (48.9%) were disinfectant air‐freshening sprays, 76 (43.2%) were household cleaners, 13 (7.4%) were wet wipes and one (0.6%) was a laundry product. There were no dishwashing products containing BAK. In total, 158 (89.8%) products reported concentrations of BAK used, which ranged from 0.05% to 80%. Twenty‐two (12.5%) products had concentrations of 0.05%, while 40 (22.7%) had concentrations from 0.05% to 0.1%. Of the 40 (22.7%) BAK‐containing products promoted to be effective against COVID‐19, bacteria and viruses, 34 (85.0%) of these products did not report BAK concentrations. Of the 18 (10.2%) products promoted as non‐allergenic, 16 (88.9%) did not report BAK concentrations, while the other two products had BAK concentrations of 0.18% and 0.19%, respectively. Rates of worldwide contact allergy to BAK range from 1.6% to 12.1%, and have been increasing since 2017 (Veverka KK, Hall MR, Yiannias JA et al. Trends in patch testing with the Mayo Clinic Standard Series, 2011–2015. Dermatitis 2018; 29: 310–15). While local guidelines recommend concentrations of 0.05% BAK against COVID‐19, 0.1% BAK is considered safe as a cosmetic ingredient (Liebert MA. Final report on the safety assessment of benzalkonium chloride. J Am Coll Toxicol 1989; 8: 589–625), and concentrations of 0.12% have been found to be antibacterial, disrupting cell membranes in target organisms. With BAK being the second most prevalent ingredient after alcohol and found in 8.8% of hand sanitizers in the USA, there is increasing concern that continued BAK sensitization from hand sanitizers and disinfectant sprays might preclude individuals from the essential use of ophthalmic solutions, topical antiseptics and anaesthetics in future. In the era of the COVID‐19 pandemic, more judicious cleaning practices have increased use of disinfectant solution and cleaning wipes. There should be increased awareness regarding increased exposure and reported contact allergy to BAK.