Background:Children with long-term illnesses frequently experience symptoms that could negatively affect their daily lives. These symptoms are often underreported in health care. Despite a large number of mobile health (mHealth) tools, few are based on a theoretical framework or supported by scientific knowledge. Incorporating universal design when developing a product can promote accessibility and facilitate person-centered communication.

Objective: The aim of this study is to identify the symptom-reporting needs of children with cancer and congenital heart defects that could be satisfied by using a mobile app. Another aim is to evaluate how the child might interact with the app by considering universal design principles and to identify parents’ views and health care professionals’ expectations and requirements for an mHealth tool.

Methods: User-centered design is an iterative process that focuses on an understanding of the users. The adapted user-centered design process includes 2 phases with 4 stages. Phase 1 involved interviews with 7 children with long-term illnesses, 8 parents, and 19 health care professionals to determine their needs and wishes for support; a workshop with 19 researchers to deepen our understanding of the needs; and a workshop with developers to establish a preliminary tool to further investigate needs and behaviors. Phase 2 involved interviews with 10 children with long-term illnesses, 9 parents, and 21 health care professionals to evaluate the mock-up (prototype) of the mHealth tool. Data were synthesized using the interpretive description technique.

Results:A total of 4 aspects of needs emerged from the synthesis of the data, as follows: different perspectives on provided and perceived support; the need for an easy-to-use, non–clinic-based tool to self-report symptoms and to facilitate communication; the need for safety by being in control and reaching the child’s voice; and a way of mapping the illness journey to facilitate recall and improve diagnostics. The children with long-term illnesses expressed a need to not only communicate about pain but also communicate about anxiety, fatigue, fear, and nausea.

Conclusions: The findings of this study indicated that the PicPecc (Pictorial Support in Person-Centered Care for Children) app is a potential solution for providing communicative support to children with long-term illnesses dealing with multiple symptoms and conditions. The interview data also highlighted symptoms that are at risk of being overlooked if they are not included in the mobile app. Further studies are needed to include usability testing and evaluation in hospitals and home care settings.