Necrotizing external otitis: analysis of relapse risk factors in 66 patients managed during a 12 year period
Authors: Danjou William , Chabert Paul , Perpoint Thomas , Pradat Pierre , Miailhes Patrick , Boibieux André , Becker Agathe , Fuchsmann Carine , Laurent Frédéric , Tringali Stephane , Roux Sandrine , Triffault-Fillit Claire , Valour Florent , Ferry Tristan ,   Lyon Bone and Joint Infection Study Group, Ferry Tristan , Ferry Tristan , Valour Florent , Perpoint Thomas , Ader Florence , Roux Sandrine , Becker Agathe , Triffault-Fillit Claire , Simon Marie , Conrad Anne , Pouderoux Cécile , Chauvelot Pierre , Chabert Paul , Lippman Johanna , Braun Evelyne , Lustig Sébastien , Servien Elvire , Batailler Cécile , Gunst Stanislas , Schmidt Axel , Sappey-Marinier Elliot , Ode Quentin , Fessy Michel-Henry , Viste Anthony , Besse Jean-Luc , Chaudier Philippe , Louboutin Lucie , Van Haecke Adrien , Mercier Marcelle , Belgaid Vincent , Gazarian Aram , Walch Arnaud , Bertani Antoine , Rongieras Frédéric , Martres Sébastien , Trouillet Franck , Barrey Cédric , Mojallal Ali , Brosset Sophie , Hanriat Camille , Lherm Mathilde , Person Hélène , Céruse Philippe , Fuchsmann Carine , Gleizal Arnaud , Aubrun Frédéric , Dziadzko Mikhail , Macabéo Caroline , Patrascu Dana , Laurent Frederic , Beraud Laetitia , Roussel-Gaillard Tiphaine , Dupieux Céline , Kolenda Camille , Josse Jérôme , Craighero Fabien , Boussel Loic , Pialat Jean-Baptiste , Morelec Isabelle , Tod Michel , Gagnieu Marie-Claude , Goutelle Sylvain , Piron Catherine , Mabrut Eugénie 
Published: June 2022

Abstract

Background
Necrotizing external otitis (NEO) is a severe infection of the skull base that occurs generally in the elderly and/or in diabetic recipients. There are few data in the literature about the therapeutic management of this complex bone infection.

Objectives
To analyse relapses after NEO treatment completion, and to describe the clinical features of NEO.

Methods
We performed a retrospective cohort study in the Lyon regional reference centre for the management of complex bone and joint infections. Consecutive cases of NEO from 1 January 2006 to 31 December 2018 were included. The primary outcome was the relapse of NEO. Variables were analysed using Cox regression survival analysis with adjusted hazard ratio (aHR) and Kaplan–Meier curve.

Results
Sixty-six patients were included. Median age was 75 (IQR 69–81) years and 46 (70%) patients were diabetic. Eleven patients (17%) had temporomandibular arthritis, 10 (15%) cranial nerve paralysis, 2 (3%) cerebral thrombophlebitis, and 2 (3%) contiguous abscess. Microbiological documentation was obtained in 56 patients and revealed Pseudomonas aeruginosa in 44/56 patients (79%). Nine (14%) cases had no microbiological documentation. Antibiotic therapy was dual for 63 (95%) patients. During a median follow-up of 27 (IQR 12–40) months, 16 out of 63 (25%) patients experienced a relapse. Fungal infection was significantly associated with relapse [aHR 4.1 (95% CI 1.1–15); P = 0.03].

Conclusions
NEO is a severe bone infection, mainly (but not exclusively) caused by P. aeruginosa, which occurs in elderly and diabetic recipients. Fungal infections at baseline significantly impact the outcome.