Several hundred million citizens suffer from allergic diseases, ranging from watery eyes to life-threatening anaphylactic shock. In addition to the individual reduction of quality of life, allergies have an impact on workplace efficiency and healthcare budgets. Although new developments of diagnostic assays are advancing quickly, their implementation in clinical routine is challenged by several barriers. This is very evident in the EU, where the gap between technological progress and modern diagnosis is rapidly growing. Digital Health tackles this challenge by providing novel tools, supporting allergy diagnosis and treatment through internet platforms, medical devices, smart-phone apps, telemedicine tools, etc. The integration of Digital Health procedures and tools in the management of allergic diseases will allow personalized diagnostic and therapeutic approaches with 24/7 interactivity between patients and professional healthcare. It will enable the delivery of faster, relevant healthcare support via real-time accessibility of key information for specialists, at primary health care centers, pharmacies and the patient´s home.  "Digital Allergology: From Theory to Practice" is unique in comprehensively approaching "Digital Allergology", starting with the general frame to more specific parts on specific allergic diseases, public health as well as research and perspectives from several countries. Allergology being transversal, and covering dozen sub-specialty areas, the list of authors, each one with specific expertise in Digital Health applied to his/her sub-area of interest, is heterogeneous: same sub-areas will be seen from different perspectives. Built for allergists and other clinicians with a strong interest in allergic diseases, it will be a stimulating read for allied health professionals, insurance companies, public health administrators, manufacturers in allergen immunotherapy, IT developers, and clinical scientists.