Background: Recurrent infections of the nose, sinuses, and ears are common problems of people with primary ciliary dyskinesia (PCD). While pulmonary exacerbations in PCD are defined, there is no definition for Ear-Nose-Throat (ENT) exacerbations, a potential outcome for research and clinical trials.

Methods: We set up an expert panel of 24 ENT specialists, patients, respiratory physicians, and other healthcare professionals, to develop consensus definitions of sinonasal and otologic exacerbations in children and adults with PCD for research settings. We reviewed the literature and used a modified Delphi approach with 4 electronic surveys.

Results: Both definitions are based on a combination of major and minor criteria, requiring 3 major or 2 major and at least 2 minor criteria each. Major criteria for a sinonasal exacerbation are: 1) reported acute increase in nasal discharge or change in colour; 2) reported acute pain/sensitivity in the sinus regions;  3) mucopurulent discharge on examination. Minor criteria include: reported symptoms; examination signs; doctorŽs decision to treat;  improvement after at least 14-days. Major criteria for the otologic exacerbation are: 1) reported acute ear pain/sensitivity, 2) reported acute ear discharge, 3) ear discharge on examination, 4) signs of otitis media in otoscopy. Minor criteria are: reported acute hearing problems; signs of acute complication; doctorŽs decision to treat.

Conclusion: These definitions might offer a useful outcome measure for PCD research in different settings. They should be validated in future studies and trials together with other potential outcomes, to assess their usability.

Funding: SNF PZ00P3_185923, BEAT-PCD