Anaphylaxis is a severe and potentially life-threatening allergic reaction that requires immediate treatment. A proposal for the development of a mobile application for supporting anaphylaxis patients was written by a team of allergists, after which this study was performed in order to identify critical success factors for the adoption of such an app. A mixed- method approach is used in order to gather data from a variety of sources, comprising a literature review, a domain expert interview, and a patient survey. One of the most valuable factors proved to be the validation of the medical information provided in the app. Besides this, patients are mostly concerned with the clarity of the presented information. While the proposed app does not fulfill all the identified factors, its development is overseen by medical professionals and endorsed by patient organizations. With a lack of such apps in the Dutch market and the demand indicated by survey respondents, this app has the potential to fill a gap in the support of anaphylaxis patients.