Is Quaternium-15 a Formaldehyde Releaser? Correlation between Positive Patch Test Reactions to Formaldehyde and Quaternium-15

BACKGROUND: The question of whether quaternium-15 is a formaldehyde releaser is controversial. Understanding this relationship is critical because of the widespread use of quaternium-15 and the need to properly advise formaldehyde-allergic individuals. OBJECTIVES: This study aimed to look for an association between allergy to quaternium-15 and formaldehyde by correlating reactions to both and to correlate the intensity of positive patch test results to formaldehyde with reactivity to quaternium-15. METHODS: This is a retrospective analysis of 1905 patients who underwent patch testing for allergic contact dermatitis. Associations were analyzed by χ testing. RESULTS: Of all patients, 9.5% reacted to quaternium-15, 7.2% reacted to formaldehyde, and 5.4% reacted to both (P < 0.001). Of 137, 86 had strong (2 or 3+) and 51 had weak (1+ or +/-) formaldehyde reactions; there was no relationship between the severity of formaldehyde reactivity and responsiveness to quaternium-15 (P = 0.229). Sex analysis did not change these findings. LIMITATIONS: This study is limited by its retrospective analysis and small sample size. CONCLUSIONS: A statistically significant relationship exists between reactivity to quaternium-15 and formaldehyde; however, the severity of the formaldehyde reaction does not predict reactivity to quaternium-15. Despite coreactivity with formaldehyde, quaternium-15 may not be a significant formaldehyde releaser. The coreactivity between quaternium-15 and formaldehyde requires further studies.