In this paper, we aimed to address the problem of diaper dermatitis (DD) in newborns caused by delayed diaper changes. We designed a real-time diaper moisture monitoring system based on IoT technology. The perception layer utilizes a 433 MHz radio frequency (RF433) wireless transmission module and a moisture sensor to achieve low-power, real-time, and low-interference detection. When a diaper moisture threshold is reached, the system immediately notifies the caregiver via an alarm module and simultaneously transmits the data to a backend server via the protocol Message Queuing Telemetry Transport (MQTT) using a microprocessor at the transmission layer. The data processing layer utilizes an Application Programming Interface (API) and a database for storage and statistical analysis. The application layer includes Web and Application (APP) interfaces to simultaneously monitor the status of multiple patients across multiple platforms and provides real-time push notifications for alerts. Clinical trials have demonstrated that this system effectively reduces the incidence of DD and hospital stays, thereby improving overall care quality. In this research, we also showed that while MQTT offers real-time performance but exhibits significant latency, APIs provide greater stability and minimal latency, making them suitable for real-time display and management. Overall, this system demonstrates high scalability and practicality, and is poised for future expansion into long-term care and elderly care settings.