Persistent Reaction to Bacitracin after Patch Testing with Thin Layer Rapid Use Epicutaneous Test

Long-lasting allergic patch test reactions (LLAPTR) are reactionsthat remain positive for two weeks or more after the applicationof the allergen. LLAPTR of longer than 6 weeks durationis rarely seen. Here we present a 54-year-old femalepatient who had a positive allergic reaction to bacitracin withthe thin layer rapid use epicutaneous test (TRUE test), whichlasted for about 11 weeks duration. To our knowledge this isthe first reported case of LLAPTR related to the bacitracin.