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® in comparison with a standardly used device, AquaFlux AF200® , for measuring TEWL. METHODS: Transepidermal water loss measurements by gpskin Barrier Light® and AquaFlux AF200® in ichthyotic and healthy skin were compared. RESULTS: AquaFlux AF200® TEWL readings were consistently higher than those from gpskin Barrier Light® . 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® and AquaFlux AF200® 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.

Transepidermal water loss in the orphan forms of ichthyosis.

As a surrogate measure of skin barrier dysfunction, we sought to determine differences in transepidermal water loss (TEWL) among ichthyosis subtypes and correlate TEWL with clinical severity. Subjects with Netherton syndrome had the highest TEWL values (increased water loss), while TEWL values were lowest in subjects with epidermolytic ichthyosis. TEWL correlated with severity only in lamellar ichthyosis and age was inversely correlated with TEWL (rs  = -.213, P = .02). TEWL is an objective measure that complements disease severity in ichthyosis and may be used as an adjuvant to monitor treatment response.