Can a handheld device accurately measure barrier function in ichthyoses?

Background Transepidermal water loss (TEWL) is a surrogate measure of skin barrier dysfunction. Historically, devices that measure TEWL are expensive, complex, and require connection to a computer and energy source. Consequently, measurement of skin's TEWL has been limited to the research setting. Objectives Evaluate the accuracy of the handheld device gpskin Barrier Light(R)in comparison with a standardly used device, AquaFlux AF200(R), for measuring TEWL. Methods Transepidermal water loss measurements by gpskin Barrier Light(R)and AquaFlux AF200(R)in ichthyotic and healthy skin were compared. Results AquaFlux AF200(R)TEWL readings were consistently higher than those from gpskin Barrier Light(R). In the pooled cohort, TEWL values were strongly correlated and both devices had excellent reliability. When subjects and controls were examined separately, there was moderate correlation between devices, with stronger agreement at higher TEWL values. Limitations Transepidermal water loss was determined at one time point. There is no formally established industry standard TEWL-assessing device. Conclusion Although gpskin Barrier Light(R)and AquaFlux AF200(R)devices cannot be used interchangeably, correlation in measuring TEWL was strong in patients with skin disease. This finding suggests that the low-cost, handheld device can accurately capture change in TEWL to track disease improvement.