Wearable System Using Printed Interdigitated Capacitive Sensor for Monitoring Atopic Dermatitis in Patients

Recent advances in sensor technology offer the potential to transform dermatology by enabling continuous monitoring and objective, data-driven assessment of skin conditions. This work presents a novel wearable device for non-invasive assessment of atopic dermatitis (AD) severity in patients. The device uses a bespoke interdigitated capacitor (IDC) sensor, sensitive only to biomarkers of AD, namely stratum corneum (SC) hydration. The sensor is integrated into a flexible textile armband and paired with a compact readout circuit, capable of transmitting real-time SC hydration data via a custom graphical user interface (GUI). The device exhibited excellent measurement repeatability and stability under different environmental conditions. It was tested on 13 patients with the condition and demonstrated strong correlation with the standard clinical assessment tools such as the Corneometer ( $r =0.595$ , $p\lt 0.05$ ). The e-textile IDC sensor identified a difference of 3–5 pF between skin with symptoms of the condition compared to skin without, while showing significantly less variability compared to the Corneometer. The improved stability and accuracy, combined with the conformal form-factor and ability to perform continuous measurements make the e-textile IDC sensor a much better candidate for at-home monitoring of AD in patients, compared to the current standard tools.