Associated positive patch test reactions to standard contact allergens.
BACKGROUND
Patch testing with a standard allergen series often yields positive reactions to more than 1 allergen in a patient.


OBJECTIVE
To identify all significantly associated pairs of positive reactions and to assess their relation to the strength of the reactions and to the irritative potential of the allergens.


METHODS
Based on the filed data of 57,822 patients, associations between positive reactions to 2 different allergens were quantified with odds ratios. Statistical methods included Fisher's exact test, the Bonferroni adjustment to account for the effect of multiple testing, and the Spearman rank correlation.


RESULTS
Out of the 32,779 patients with complete readings of 24 standard allergens, 7,501 had shown more than 1 positive reaction. Statistically significant associations were detected for 166 out of the 276 possible different combinations of 2 distinct positive reactions, including combinations that had not been identified before. Patients with a strong reaction or a positive reaction to an allergen with a high irritative potential tended to have additional positive reactions to further allergens more often than others, but the number of significant associations was not dependent on these parameters.


CONCLUSIONS
There are more significant associations that have to be taken into account for patch testing than has been known so far. Although irritation can favor a higher number of positive reactions, significant associations of positive reactions to distinct allergens are probably caused by other mechanisms that require further analyses.
Brasch
J
J
Department of Dermatology, University of Kiel, Kiel, Germany. jbrasch@dermatology.uni-kiel.de
Uter
W
W
Geier
J
J
Schnuch
A
A
D000328:Adult; D000485:Allergens; D017449:Dermatitis, Allergic Contact / Q000175:diagnosis* / Q000473:pathology; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D008297:Male; D010328:Patch Tests / Q000379:methods / Q000592:standards*
D000485:Allergens