Sensitivity of Various Skin Sites in the Repeated Open Application Test

Abstract

The sensitivity of various skin sites in the repeated open application test (ROAT) was studied. The substances were mostly ingredients of dermatologic vehicles producing allergic or questionable reactions in routine patch tests. About 0.4-mL aliquots of test substances were applied to 10 × 10 cm areas twice daily for 7 days. ROAT were conducted simultaneously on two out of the following five areas: the ventral aspect of the lower arm (LA), the antecubital fossa (AF), the outer aspect of the upper arm (UA), the back skin (BS) over the scapula, and the forehead (FH). The sensitivity decreased in the following order: BS ≥ UA ≥ AF > LA. The FH was less sensitive than the upper extremity, the BS, and the AF. Thus, it seems that the AF, the UA, and the BS are the areas of choice for the ROAT.