Background:The body of knowledge regarding rhinosinusitis (RS) continues to expand, with rapid growth in number of publications, yet substantial variability in the quality of those presentations. In an effort to both consolidate and critically appraise this information, rhinologic experts from around the world have produced the International Consensus Statement on Allergy and Rhinology: Rhinosinusitis (ICAR:RS). Methods:Evidence-based reviews with recommendations (EBRRs) were developed for scores of topics, using previously reported methodology. Where existing evidence was insufficient for an EBRR, an evidence-based review (EBR) was produced. The sections were then synthesized and the entire manuscript was then reviewed by all authors for consensus. Results:The resulting ICAR:RS document addresses multiple topics in RS, including acute RS (ARS), chronic RS (CRS) with and without nasal polyps (CRSwNP and CRSsNP), recurrent acute RS (RARS), acute exacerbation of CRS (AE-CRS), and pediatric RS. Conclusion:As a critical review of the RS literature, ICAR:RS provides a thorough review of pathophysiology and evidence-based recommendations for medical and surgical treatment. It also demonstrates the significant gaps in our understanding of the pathophysiology and optimal management of RS. Too o en the foundation upon which these recommendations are based is comprised of lowerlevel evidence. It is our hope that this summary of the evidence in RS will point out where additional research efforts may be directed. C 2016 ARS-AAOA, LLC. Key Words:rhinosinusitis; chronic rhinosinusitis; acute rhinosinusitis; recurrent acute rhinosinusitis; evidence-based medicine; systematic review; endoscopic sinus surgery List of Abbreviations Used

I. Executive Summary Background The 5 years since the publication of the first International Consensus Statement on Allergy and Rhinology: Rhinosinusitis (ICAR‐RS) has witnessed foundational progress in our understanding and treatment of rhinologic disease. These advances are reflected within the more than 40 new topics covered within the ICAR‐RS‐2021 as well as updates to the original 140 topics. This executive summary consolidates the evidence‐based findings of the document. Methods ICAR‐RS presents over 180 topics in the forms of evidence‐based reviews with recommendations (EBRRs), evidence‐based reviews, and literature reviews. The highest grade structured recommendations of the EBRR sections are summarized in this executive summary. Results ICAR‐RS‐2021 covers 22 topics regarding the medical management of RS, which are grade A/B and are presented in the executive summary. Additionally, 4 topics regarding the surgical management of RS are grade A/B and are presented in the executive summary. Finally, a comprehensive evidence‐based management algorithm is provided. Conclusion This ICAR‐RS‐2021 executive summary provides a compilation of the evidence‐based recommendations for medical and surgical treatment of the most common forms of RS.

Allergic rhinitis (AR) is a global health problem that causes major illnesses and disabilities worldwide. Epidemiologic studies have demonstrated that the prevalence of AR has increased progressively over the last few decades in more developed countries and currently affects up to 40% of the population worldwide. Likewise, a rising trend of AR has also been observed over the last 2–3 decades in developing countries including China, with the prevalence of AR varying widely in these countries. A survey of self-reported AR over a 6-year period in the general Chinese adult population reported that the standardized prevalence of adult AR increased from 11.1% in 2005 to 17.6% in 2011. An increasing number of original articles and imporclinical trials on the epidemiology, pathophysiologic mechanisms, diagnosis, management and comorbidities of AR in Chinese subjects have been published in international peer-reviewed journals over the past 2 decades, and substantially added to our understanding of this disease as a global problem. Although guidelines for the diagnosis and treatment of AR in Chinese subjects have also been published, they have not been translated into English and therefore not generally accessible for reference to non-Chinese speaking international medical communities. Moreover, methods for the diagnosis and treatment of AR in China have not been standardized entirely and some patients are still treated according to regional preferences. Thus, the present guidelines have been developed by the Chinese Society of Allergy to be accessible to both national and international medical communities involved in the management of AR patients. These guidelines have been prepared in line with existing international guidelines to provide evidence-based recommendations for the diagnosis and management of AR in China.