Patch tests with thiurams at 0.25% pet. and 1% pet. are of equal diagnostic value.
Thiuram mix is tested in the standard series at a test concentration of 1% pet. The single thiurams (DPTD, TMTD, TMTM, TETD), however, are usually tested at 0.25% pet. in Germany. In other countries, the individual components of thiuram mix are tested at 1% pet. The German Contact Dermatitis Research Group (DKG) compared both patch test concentrations in 530 patients in order to find out if (i) a significant number of positive patch tests are missed by testing at the lower concentration, (ii) problems with irritant test reactions occur by increasing the test concentration to 1%, and (iii) the sensitivity of the thiuram mix rises when the breakdown test is done with the higher concentration. Slightly more positive reactions were seen with the higher concentration, but this increase did not reach statistical significance. The reaction index, as a measure for the relation of positive to irritant and/or questionable reactions, remained unchanged for the individual thiurams. The sensitivity of the mix also did not change when the breakdown test was performed with 1% pet. instead of 0.25% pet. Thus, we conclude that both concentrations are of equal diagnostic value in patch testing.
Geier
Johannes
J
Information Network of Department of Dermatology, University of Göttingen, Germany. jgeier@med.uni-goettingen.de
Frosch
Peter J
PJ
Schnuch
Axel
A
Agathos
Monika
M
Bauer
Andrea
A
Brasch
Jochen
J
Gaber
Gisela
G
Gottlöber
Petra
P
Grabbe
Jürgen
J
Hartmann
Martin
M
Jappe
U T A
UT
Kaatz
Martin
M
Lübbe
Dieter
D
Pirker
Claudia
C
Gefeller
Olaf
O
D017449:Dermatitis, Allergic Contact / Q000175:diagnosis*; D006801:Humans; D010328:Patch Tests; D010577:Petrolatum; D012680:Sensitivity and Specificity; D013893:Thiram / Q000009:adverse effects
D013893:Thiram; D010577:Petrolatum