Acute otitis externa: Consensus definition, diagnostic criteria and core outcome set development

Objective: Evidence for the management of acute otitis externa (AOE) is limited, with unclear diagnostic criteria and variably reported outcome measures that may not reflect key stakeholder priorities. We aimed to develop 1) a definition, 2) diagnostic criteria and 3) a core outcome set (COS) for AOE.

Study design: COS development according to Core Outcome Measures in Effectiveness Trials (COMET) methodology and parallel consensus selection of diagnostic criteria/definition.

Setting: Stakeholders from the United Kingdom.

Subjects and methods: Comprehensive literature review identified candidate items for the COS, definition and diagnostic criteria. Nine individuals with past AOE generated further patient-centred candidate items. Candidate items were rated for importance by patient and professional (ENT doctors, general practitioners, microbiologists, nurses, audiologists) stakeholders in a three-round online Delphi exercise. Consensus items were grouped to form the COS, diagnostic criteria, and definition.

Results: Candidate COS items from patients (n = 28) and literature (n = 25) were deduplicated and amalgamated to a final candidate list (n = 46). Patients emphasised quality-of-life and the impact on daily activities/work. Via the Delphi process, stakeholders agreed on 31 candidate items. The final COS covered six outcomes: pain; disease severity; impact on quality-of-life and daily activities; patient satisfaction; treatment-related outcome; and microbiology. 14 candidate diagnostic criteria were identified, 8 reaching inclusion consensus. The final definition for AOE was 'diffuse inflammation of the ear canal skin of less than 6 weeks duration'.

Conclusion: The development and adoption of a consensus definition, diagnostic criteria and a COS will help to standardise future research in AOE, facilitating meta-analysis. Consulting former patients throughout development highlighted deficiencies in the outcomes adopted previously, in particular concerning the impact of AOE on daily life.


Matthew E. Smith, John C. Hardman, Nishchay Mehta, Gareth H. Jones, Rishi Mandavia, Caroline Anderson, Maha Khan, Aula Abdelaziz,Bakir Al-Dulaimy,Nikul Amin,Rajesh Anmolsingh,Bilal Anwar,Manohar Bance,Katherine Belfield,Mahmood Bhutta,Ruaridh Buchanan,Deepak Chandrasekharan,Michael Chu,Srikanth Chundu,Katherine Conroy,Gemma Crundwell,Mat Daniel,Jessica Daniels,Sujata De,Sian Dobbs,Jayesh Doshi,Matthew Farr,Tanjinah Ferdous,Eleni Fragkouli,Simon Freeman,Samit Ghosh,Emma Gosnell,S. Alam Hannan,Elliot Heward,Faisal Javed,Deepa John,Helen Nicholls,Anand V. Kasbekar,Haroon Khan,Hammad Khan,Sadie Khwaja,Bhik Kotecha,Madhankumar Krishnan,Nirmal Kumar,Tamara Lamb,Hannah Lancer,Joseph G. Manjaly,Marcos Martinez Del Pero,Fiona McClenaghan,Kristijonas Milinis,Nina Mistry,Hassan Mohammed,Elizabeth Morris,Stephen Morris-Jones,Jessica Padee,Surojit Pal,Sanjay Patel,Agamemnon Pericleous,Asad Qayyum,Maral Rouhani,Haroon Saeed,Mirusanthan Santhiyapillai,Kay Seymour,Sunil Sharma,Richard Siau,Arvind Singh,Emma Stapleton,Kate Stephenson,Gill Stynes,Bharathi Subramanian,Neil Summerfield,Chloe Swords,Aaron Trinidade,Antonia Tse,Emmanuel Twumasi,Harmony Ubhi,Samit Unadkat,Ananth Vijendren,Joe Wasson,Glen Watson,Glennis Williams,Janet Wilson,Alexander Yao,Ahmed Youssef,Simon K. W. Lloyd,James R. Tysome,on behalf of INTEGRATE (The UK ENT Trainee Research Network)


Journal: PLoS One
Volume: 16
Issue: 5
Pages: -
Year: 2021
DOI: 10.1371/journal.pone.0251395

Further Study Information

Current Stage: Completed
Date: January 2019 - September 2019
Funding source(s): None

Health Area

Disease Category: Ear, nose, & throat

Disease Name: Acute otitis externa

Target Population

Age Range: 16 - 100

Sex: Either

Nature of Intervention: Any

Stakeholders Involved

- Clinical experts
- Consumers (patients)
- Service users

Study Type

- COS for clinical trials or clinical research


- Delphi process
- Interview
- Literature review

Candidate outcome measures will be derived from literature review of otitis externa studies and structured interviews with patients who have had otitis externa. A three round Delphi study will be used to assess stakeholder opinion of the importance of different outcomes, reaching consensus on inclusion of an outcome into the core set when pre-set criteria are reached.

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