Routine diagnostic patch-testing with formaldehyde 2.0% (0.6 mg/cm2) may be an advantage compared to 1.0%.
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.
Hauksson
Inese
I
Department of Occupational and Environmental Dermatology, Lund University, Skåne University Hospital, Malmö, Sweden.
Pontén
Ann
A
Gruvberger
Birgitta
B
Isaksson
Marléne
M
Bruze
Magnus
M
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017449:Dermatitis, Allergic Contact / Q000175:diagnosis*; D004305:Dose-Response Relationship, Drug; D005260:Female; D005557:Formaldehyde; D006801:Humans; D007509:Irritants; D008297:Male; D008875:Middle Aged; D010328:Patch Tests / Q000379:methods*; D011237:Predictive Value of Tests; D013548:Sweden; D055815:Young Adult
D007509:Irritants; D005557:Formaldehyde