Chronic care management is dependent on productive interactions between patients and healthcare professionals. Digital health technologies (eHealth) open up new possibilities for improving the quality of care, but there is a limited understanding of what productive interactions entail. This study explores characteristics of productive interactions to support self-care and healthcare in the context of eHealth use in diabetes care. We collected qualitative data based on interviews with nurses and responses to open-ended survey questions from patients, prior to and post using an eHealth service for self-monitoring and digital communication. We found that eHealth’s influence on productive interactions was characterized by unconstrained access, health parameter surveillance, and data-driven feedback, with implications for self-care and healthcare. Our findings indicate that eHealth perforates the boundaries that define interactions under traditional, non-digital care. This was manifested in expressions of uncertainty and in blurred boundaries between self-care and healthcare. We conclude that the attainment of a sustainable eHealth ecosystem will require healthcare to acknowledge eHealth as a disruptive change that may require re-organization to optimally support the productive use of eHealth services for both patients and staff, which includes agreement on new routines, as well as social interaction rules.