Prognosticating patients with necrotising otitis externa based on response to treatment

Necrotising otitis externa (NOE) is a severe infection of the temporal bone. The traditional severity based staging system does not fully prognosticate all patients with NOE. We hypothesise that a patient response staging system would more accurately capture the disease process and guide prognosis.

We carried out a retrospective notes review of patients diagnosed with NOE from January 2017 to December 2018 in a regional tertiary referral centre. Patient outcomes from our proposed patient response staging system were compared to a modified previously published severity based Gleeson staging system with patients requiring prolonged treatment classified as having a poor outcome.

A total of 34 patients were treated for NOE. The majority were male (n=24) and had diabetes (n=25). Patients with the most severe Gleeson staging did not have the worst outcome. Daily delay in resolution of otorrhoea was associated with an increased need for more than six weeks of treatment. Rapid responders are patients who had resolution of otalgia, otorrhoea and C-reactive protein normalisation within 14 days, and all were cured following standard 6 weeks of treatment.

The Gleeson staging system was valuable in assessing the extent of disease and all early Gleeson staged patients had good outcomes. However, patients with higher severity staging on the Gleeson system did not necessarily require prolonged treatment. There is a role for a joint approach in staging patients based on both modified Gleeson and treatment response, which would subsequently guide prognosis, duration of treatment and early diagnosis of potential fungal NOE.