Malignant otitis externa: experience with hyperbaric oxygen therapy

With the low incidence of malignant otitis externa (MOE) and its variable manifestations, it is not possible to perform relevant prospective controlled studies in this condition. Therefore, the best evidence on which to base therapeutic decisions is likely to remain retrospective reviews of case series. Even though our knowledge in regard to MOE is not greatly increased by the retrospective case series by Saxby et al in this issue, nevertheless it has value.1 The larger number of cases here confirms that multimodal therapy, with the inclusion of hyperbaric oxygen therapy (HBOT), enables a reduction in mortality compared to earlier case reports without HBOT. This case series is the largest in the literature. The real value of HBOT for MOE remains unclear, in part because in historical reports, patients were probably treated with less efficient antibiotics and surgical procedures than nowadays. It would have been interesting to know whether the fatal cases described here had predominantly intracranial propagation of the infection, because a particularly bad prognosis is expected in these patients even without facial nerve palsy. Cures in this high-risk subgroup would have also been worth mentioning. The number of surgical debridements required was noticeably low in this group of patients. One must bear in mind that necrotic tissue cannot be revitalised by HBOT and generally hinders cure. This syndrome of 'necrotizing' infection carries the suffix 'malignant' with good reason, given the high mortality rates reported in the literature. In summary, multimodal therapy is to be recommended for malignant otitis externa. There is no evidence to justify omitting any of the components of the treatment complex, including HBOT; there is currently no high level evidence-based medicine, just sound common sense, for any of the applied measures.