Florian Anzengruber1, Fayez Alotaibi1, Lilian S Kaufmann1, Adhideb Ghosh2, Martin R Oswald3, Julia-Tatjana Maul1, Barbara Meier1, Lars E French1, Mathias Bonmarin4, Alexander A Navarini5. 1. Department of Dermatology, University Hospital Zurich, Zurich, Switzerland; Faculty of Medicine, University of Zurich, Zurich, Switzerland. 2. Department of Dermatology, University Hospital Zurich, Zurich, Switzerland; Faculty of Medicine, University of Zurich, Zurich, Switzerland; Competence Center Personalized Medicine, University of Zurich and ETH Zurich, Zurich, Switzerland. 3. Department of Computer Science, University of Zurich and ETH Zurich, Zurich, Switzerland. 4. School of Engineering, Zurich University of Applied Sciences, Winterthur, Switzerland. 5. Department of Dermatology, University Hospital Zurich, Zurich, Switzerland; Faculty of Medicine, University of Zurich, Zurich, Switzerland; Competence Center Personalized Medicine, University of Zurich and ETH Zurich, Zurich, Switzerland. Electronic address: alexander.navarini@usz.ch.
Abstract
BACKGROUND: Patch testing of contact allergens to diagnose allergic contact dermatitis (ACD) is a traditional, useful tool. The most important decision is the distinction between allergic and irritant reactions, as this has direct implications on diagnosis and management. Our objective was to evaluate a new method of non-contact infrared reading of patch tests. Secondary objectives included a possible correlation between the intensity of the patch test reaction and temperature change. METHODS: 420 positive reactions from patients were included in our study. An independent patch test reader assessed the positive reactions and classified them as allergic (of intensity + to +++) or irritant (IR). At the same time, a forward-looking infrared (FLIR) camera attachment for an iPhone was used to acquire infrared thermal images of the patch tests, and images were analyzed using the FLIR ONE app. RESULTS: Allergic patch test reactions were characterized by temperature increases of 0.72 ± 0.67 °C compared to surrounding skin. Irritant reactions only resulted in 0.17 ± 0.31 °C temperature increase. The mean temperature difference between the two groups was highly significant (p < 0.0001) and therefore was used to predict the type of contact dermatitis. CONCLUSIONS: Thermography is a reliable and effective way to distinguish between allergic and irritant contact dermatitis.
BACKGROUND: Patch testing of contact allergens to diagnose allergic contact dermatitis (ACD) is a traditional, useful tool. The most important decision is the distinction between allergic and irritant reactions, as this has direct implications on diagnosis and management. Our objective was to evaluate a new method of non-contact infrared reading of patch tests. Secondary objectives included a possible correlation between the intensity of the patch test reaction and temperature change. METHODS: 420 positive reactions from patients were included in our study. An independent patch test reader assessed the positive reactions and classified them as allergic (of intensity + to +++) or irritant (IR). At the same time, a forward-looking infrared (FLIR) camera attachment for an iPhone was used to acquire infrared thermal images of the patch tests, and images were analyzed using the FLIR ONE app. RESULTS:Allergic patch test reactions were characterized by temperature increases of 0.72 ± 0.67 °C compared to surrounding skin. Irritant reactions only resulted in 0.17 ± 0.31 °C temperature increase. The mean temperature difference between the two groups was highly significant (p < 0.0001) and therefore was used to predict the type of contact dermatitis. CONCLUSIONS: Thermography is a reliable and effective way to distinguish between allergic and irritant contact dermatitis.
Authors: Tommy Du; Deependra K Mishra; Leonid Shmuylovich; Andy Yu; Helena Hurbon; Steven T Wang; Mikhail Y Berezin Journal: J Biophotonics Date: 2020-06-18 Impact factor: 3.207