Allergy and hypersensitivity, originally perceived as rare disorders, are one of the fastest growing conditions worldwide becoming a major public health problem and the numerous reports over the last 20 years have been indicating that the world is dealing with an allergy epidemic. The allergic and hypersensitivity conditions are complex, covering a myriad of clinical presentations, some able to be overlapped with other specialties, such as Dermatology, Pulmonology, Otorhinolaryngology, Ophthalmology, Pediatrics and Gastroenterology among others. The current concepts used in the daily basis in the clinical practice by allergists are not widely known by the "sister-specialties" resulting in misclassification and/or under-representation of these entities in health classification and coding systems so far, with a tremendous negative impact to the Allergy specialty at many different levels. Since these systems are the basis of collecting primary and secondary data related to healthcare, stakeholders have been delineating actions, support and investments according to the data generated by these registries. Therefore, the weak identity of our specialty in the international health classification and coding systems, such as the International Classification of Diseases (ICD), contributes to the lack of ascertainment and recognition of their importance for healthcare planning and resource allocation, and prevents clinical research from being performed.

A better classification of allergic and hypersensitivity conditions in international health classification and coding systems can provide a real-world scenario of our specialty based on reliable data able to support education, clinical practice and research. The implementations can in fact advocate in favor of the identity, visibility and recognition of Allergy as a specialty.

Understanding that the ICD-11 revision would be an opportunity to standardize the code definitions for all allergic and hypersensitivity conditions, an international collaboration of Allergy Academies, including World Allergy Organization, American Academy of Allergy Asthma and Immunology and European Academy of Allergy and Clinical Immunology, has been coordinating efforts since 2013 to provide a better classification of these disorders in the new ICD-11.

To call attention to the inadequacy of the ICD-10 to allergic and hypersensitivity conditions and to contribute to improvements to be made in the ICD-11 revision, we firstly proposed a global survey of healthcare professionals' attitudes toward allergic disorders classification [5]. Meanwhile, we entered on bilateral discussion with representatives of the WHO ICD-11 revision. Following a careful comparison of ICD-10 and 11 beta phase linearization, we could identify gaps, trade-offs and areas of regression in allergy coding [4]. This process was the building block for the construction of an allergic and hypersensitivity classification proposal following the ICD/WHO rules in particular with the aim to be used by allergists, nonallergists and nonphysicians. The classification proposal was validated by crowdsourcing the allergy academies' leadership community. As a result, a high level complex structure of classification for allergic and hypersensitivity conditions has been constructed and offered to the WHO groups in charge of the ICD revision for endorsement [6]. To facilitate the acceptance of the proposed classification model, we aligned the constructed classification to the ICD-11 beta draft by a cross-linking terms process. We could underline the need for a chapter in ICD-11 addressed to the disorders covered by our specialty [7].

During the WHO meeting in December 2014, we could present details of the historic-prospective strategic actions (Fig. 1) to the revising steering group (RSG) WHO responsible for the revision of the ICD and the pediatric topic advisory group and discuss feasible ways of having a better classification of allergic and hypersensitivity conditions into the ICD-11 structure. All the actions and the support of the academies were fully appreciated by the WHO representatives, who advised us to perform a simplification process to fit our classification proposal to the ICD-11 framework [8]. Following the meeting, we carried on intensive dialog with the RSG WHO representatives and with their guidance; the "allergic and hypersensitivity conditions" parented subchapter has been constructed under the "immune system disorders" chapter in early 2015. The building process was a detailed technical/scientific labor-intensive construction in which we had to reach a consensus with all the "sister-specialties" with whom we have overlapping conditions. As a result, the "allergic and hypersensitivity conditions" parented subchapter counts with more than 300 entities classified under 6 headings [2].

The ICD-11 beta phase is not finished and receives frequent inputs and, therefore, has to be constantly reviewed. The "allergic and hypersensitivity conditions" parented subchapter is a major achievement to the recognition and visibility of our specialty and can be considered as a milestone in the history of our specialty. However, we are aware that its development is not set. We carry on working in the dissemination and validation process with the WHO guidance and the support of the allergy academies. In this regard, we are most grateful to recently have had the support of three more regional allergy societies: the Latin American Society of Allergy, Asthma and Immunology, the American College of Allergy Asthma and Immunology, and the Asia Pacific Association of Allergy, Asthma and Clinical Immunology. Believing that the outcomes of all past and future actions will impact positively to the Allergy specialty, we expect for the full approval by the United Nations in 2017.