Background: Children with long-term illness frequently experience symptoms that affect their daily life, and this is underreported in healthcare. Despite the large number of mHealth tools, few are based on a theoretical framework or supported by scientific knowledge. Incorporating universal design when developing a product ensures that all may benefit from the design and that person-centred communication is facilitated.

Objective: Our study aimed to develop a person-centred communication support mHealth tool (i.e. Pictorial support in personcentred care for children: PicPecc) based on universal design principles for children with long-term illness to communicate their symptoms, using the co-design process by involving various stakeholder groups (children with long-term illness, parents, healthcare professionals, developers).

Methods: The co-design development process included four phases: (i) interviews with seven children, 8 parents and 19 healthcare professionals to determine needs and wishes for support, (ii) workshop with 19 researchers, (iii) workshop with developers and (iv) interviews with 10 children, 9 parents and 21 healthcare professionals to evaluate the mock-up (prototype) of the developed mHealth tool. Data were synthesised using interpretive description. 

Results: There is a need for children with long-term illness to address symptoms such as fear, fatigue, nausea, pain, and anxiety. Fatigue and anxiety may be overlooked by healthcare professionals and therefore an easy-to-use tool to facilitate communication with the children is needed. Three common aspects were constructed: different perspectives on provided and perceived support, need for an easy tool to assess symptoms and to facilitate communication, as well as mapping the journey to facilitate recall. Parent and children stakeholders expressed a need for support when dealing with psychosocial issues, while parents were simultaneously concerned that children may regard the word anxiety as too alarming. However, the children themselves did not react to the word. Researchers repeated the importance of employing easy-to-use mHealth tools for children to communicate symptoms going beyond pain, e.g. anxiety and fatigue. The developers highlighted the practical and logistical implications of suggestions offered by other stakeholders and proposed best options for the development of the tool. 

Conclusions: The co-designed developed PicPecc tool demonstrated the capacity to provide support when dealing with multiple symptoms and conditions. PicPecc opens a dialogue between the child and the healthcare professionals, and it addresses symptoms that may otherwise be overlooked. Future research includes usability testing and evaluation in hospitals, as well as in a home care setting.