Pontén, Ann2; Aalto-Korte, Kristiina2; Agner, Tove4; Andersen, Klaus Ejner2; Giménez-Arnau, Ana M2; Gonçalo, Margarida2; Goossens, An2; Johansen, Jeanne D4; Le Coz, Christophe J2; Maibach, Howard I2; Rustemeyer, Thomas2; White, Ian R2; Bruze, Magnus2
1 Section of Neurology, Psychiatry and Sensory Sciences, Department of Clinical Medicine, Faculty of Health and Medical Sciences, Københavns Universitet2 unknown3 Department of Clinical Medicine, Department of Clinical Medicine, Faculty of Health and Medical Sciences, Københavns Universitet4 Department of Clinical Medicine, Department of Clinical Medicine, Faculty of Health and Medical Sciences, Københavns Universitet
Background.The currently used patch test concentration for formaldehyde is 1.0% (wt/vol) in water. However, clinical experience and previous studies suggest that 1.0% might be insufficient for detecting an optimized number of clinically relevant cases of contact allergy to formaldehyde. Objectives.To validate earlier patch test results for comparison of 1% (wt/vol) and 2% (wt/vol) formaldehyde in water, and to investigate co-reactivity with quaternium-15. Materials and methods.In 12 dermatology clinics, 3591 patients were routinely patch tested simultaneously with 2.0% (wt/vol) (0.60 mg/cm(2) ) and 1.0% (wt/vol) (0.30 mg/cm(2) ) formaldehyde. Micropipettes were used for delivering the exact dosage of the allergen. Results.Significantly more patients reacted to 2.0% formaldehyde than to 1.0% (3.4% versus 1.8%, p <0.001). Overall, there were no sex differences between those reacting positively to 2.0% and 1.0%. Of 25 quaternium-15-positive patients, 4 (0.1%) reacted positively without reacting to formaldehyde. Conclusion.On the basis of the results of this multicentre study, as well as of previous studies, it can be suggested that 2.0% (wt/vol) in water formaldehyde should be used in routine patch testing in the baseline series.
Contact Dermatitis, 2013, Vol 68, Issue 1, p. 50-53