Researchers have developed a compact infrared sensing system that could enable more reliable at-home monitoring of skin hydration in people with atopic dermatitis. Unlike existing techniques, the new approach measures hydration beyond the skin’s surface while compensating for temperature fluctuations that often reduce measurement accuracy. The technology could help patients and clinicians monitor chronic skin conditions more objectively between hospital visits.
Atopic dermatitis, one of the most common forms of eczema, is characterized by a disrupted skin barrier, chronic inflammation and persistent dryness. Monitoring hydration levels is an important part of disease management, but current methods are often limited to superficial measurements and can be influenced by environmental conditions, making it difficult to assess the deeper skin layers where the disease is most active. According to the researchers, a simple, non-invasive tool that patients can use at home could provide a more consistent picture of disease progression and treatment response.
Improving measurement stability
The interdisciplinary team, led by researchers from the Chinese Academy of Medical Sciences & Peking Union Medical College in collaboration with the Characteristic Medical Center of the Chinese People's Armed Police Force and Cardiff University, developed a near-infrared optical system combined with a temperature-aware algorithm.
Rather than measuring water content alone, the researchers created a new optical hydration index, a digital biomarker that combines multiple optical measurements into a single hydration-related score. This approach acknowledges that skin is a biologically complex tissue rather than a simple layer of water.
The system measures both reflected near-infrared light and skin surface temperature. Temperature data are then incorporated into the algorithm to compensate for changes in water absorption, blood flow and tissue structure that can otherwise affect optical measurements. According to lead researcher Ting Li, incorporating temperature into the analysis significantly improved the robustness of the system and reduced one of the major sources of variability encountered during real-world monitoring.
Looking beyond the skin surface
One of the key challenges was accurately interpreting light reflected from deeper layers of the skin. Unlike conventional hydration sensors, which mainly assess moisture at the surface, the new system is designed to capture information from tissues beneath the epidermis.
The resulting optical hydration index integrates several physiological factors into a single measurement that better reflects overall skin condition. By accounting for the layered structure and optical complexity of human skin, the researchers were able to generate a more stable indicator of hydration than conventional superficial methods. The technology is intended to be compact and practical enough for repeated home use, allowing patients to monitor changes over time without invasive procedures or frequent clinic visits.
Personalized skin care
Although the system is still at the research stage, the findings suggest it could support more personalized management of chronic skin diseases such as atopic dermatitis. Instead of relying solely on subjective symptoms or periodic clinical assessments, patients could use objective hydration measurements to monitor whether their skin condition is improving or deteriorating.
The researchers believe the optical hydration index may eventually serve as a digital biomarker for evaluating treatment response, including the effectiveness of moisturizers and other therapies. By combining near-infrared imaging with advanced algorithms that account for biological complexity, the technology represents a step toward more reliable home-based skin monitoring.
Further research will be needed to validate the approach in larger patient populations and determine its role in routine dermatological care, but the study demonstrates how optical sensing and computational analysis could improve the long-term management of chronic inflammatory skin conditions.
