Optoacoustic mesoscopy shows potential to increase accuracy of allergy patch testing.

BACKGROUND: Differentiation between irritant and allergic skin reactions in epicutaneous patch testing is based largely on subjective clinical criteria, with the risk of high intra- and interobserver variability. Novel dermatological imaging using optoacoustic mesoscopy allows quantitative three-dimensional assessment of microvascular biomarkers. METHODS: We investigated the potential of optoacoustic imaging to improve the precision of patch test evaluation by examining 69 test reactions and 48 healthy skin sections in 52 patients with suspected type-IV-allergy. RESULTS: We identified biomarkers from the optoacoustic images. Allergic reactions were associated with higher fragmentation of skin vasculature than irritant reactions (19.5+/-9.7 vs. 14.3+/-3.7 fragments/100 pixels(2) ; P