Multiple concomitant positive patch test reactions.
Thirty-five patients who showed 90 one plus (+) patch test reactions to 28 patch test chemicals at Day 2 (D2) were retested to the chemicals at D7. On retesting, 60% (54/90) reactions were positive but 42% (38/90) were negative at D9, suggesting that false positive patch test reactions were common when more than one positive reaction was obtained by concomitant patch testing. On retesting, the total % positivity was reduced from 344 to 241 suggesting that the true index of sensitivity was falsely exaggerated by concomitant testing.
D000368:Aged; D000485:Allergens; D003877:Dermatitis, Contact / Q000175:diagnosis*; D004342:Drug Hypersensitivity / Q000175:diagnosis*; D005069:Evaluation Studies as Topic; D005189:False Positive Reactions; D006801:Humans; D008297:Male; D010328:Patch Tests / Q000379:methods*; D010655:Phenylenediamines / Q000009:adverse effects*; D012408:Rubber / Q000009:adverse effects*; D012882:Skin Tests / Q000379:methods*
D000485:Allergens; D010655:Phenylenediamines; D012408:Rubber