Regarding Use of Topical Steroids in Patients With COVID-19-Associated Olfactory Loss

I thank Dr Patel for her contribution to my recent Invited Commentary, “Treatment Recommendations for Persistent Smell and Taste Dysfunction following COVID-19—the Coming Deluge.”¹ A thoughtful analysis of available evidence is essential in determining appropriate treatment recommendations in any context, and her voice is welcome as we refine care pathways for patients with persistent olfactory dysfunction following coronavirus disease 2019 (COVID-19).

There is an ongoing need for additional high-quality studies evaluating the use of topical corticosteroid sprays and/or irrigations for the treatment of postviral olfactory dysfunction (PVOD). Although the findings introduced by Dr Patel and members of her esteemed research team represent 2 of the higher-quality studies adding evidence to this debate, they are limited by study designs that include patients with olfactory dysfunction not related to viral illness. This potential source of confounding is significant because less than 50% of enrolled participants in their randomized clinical trial had a postviral etiology associated with their symptoms.² Among this subgroup of 62 patients, only 20 (32%) showed clinical improvement. In addition, the distribution of these patients between the budesonide and control groups is unclear. Although this in no way diminishes the importance of their findings among patients with olfactory dysfunction not related to chronic rhinosinusitis (CRS), further study and nested analysis is needed to tease out outcomes among unique etiologies of olfactory dysfunction, including PVOD.

The consideration of topical corticosteroid sprays for PVOD in the setting of COVID-19 is an ongoing and welcome debate with expert recommendations both for and against their routine use.^3,4 Factors considered when recommending these sprays include their relative safety, low cost, efficacy in olfactory dysfunction related to CRS and the available evidence supporting the use of these same medications in topical irrigations. It is also important to note the emergence of an exhalation corticosteroid delivery system with improved sinonasal penetration vs traditional sprays.⁵ Although the current lack of evidence supporting corticosteroid sprays in PVOD must be acknowledged,⁶ it is my belief that future studies with increased power and the use of emerging devices with improved sinonasal distribution have the potential to demonstrate benefit, especially when used with olfactory training. It is for these reasons that I recommend both topical corticosteroids (with discussion of sprays vs irrigations) and olfactory training to patients with persistent PVOD.