Our clinical experience has suggested that the presently recommended patch-test concentration (1.0%) for formaldehyde in the baseline series might be too low. Therefore, consecutively patch-tested dermatitis patients were tested simultaneously with formaldehyde 1.0% and 2.0% (w/v) in aqua. Formaldehyde 1.0% and 2.0% were applied with a micro-pipette (15 microl) to filter paper discs in Finn Chambers (0.30 mg/cm(2) and 0.60 mg/cm(2), respectively). A total of 1397 patients with dermatitis were patch-tested. In all, 68 (4.9%) patients reacted positively to formaldehyde; 37 reacted only to 2.0%, 29 reacted to both concentrations, and 2 reacted only to 1.0%. Significantly more patients were thus diagnosed with contact allergy to formaldehyde 2.0% compared with 1.0% (p < 0.001). We detected 0.1%, 0.4%, and 29.6% irritant reactions to 1.0%, 2.0%, and 3.0% formaldehyde, respectively. We conclude that, with an optimized patch-test technique, doubling the dose per area detects significantly more contact allergies to formaldehyde, but an even higher test concentration causes too many irritant reactions to be usable.
The information about affiliations in this record was updated in December 2015.
The record was previously connected to the following departments: Occupational and Environmental Dermatology Unit (013241310), Pediatrics/Urology/Gynecology/Endocrinology (013240400)
- Dermatology and Venereal Diseases