Persistent olfactory complaints after COVID-19: a new interpretation of the psychophysical olfactory scores

Abstract

Background: Sudden olfactory loss is a major symptom of SARS-CoV-2 infection and has a negative impact on daily life quality. Almost 80% of disorders regress spontaneously. No precise characterization of the medium- and long-term olfactory symptoms has been carried out yet, apart from self-assessments. The main objective of this work was to characterize persistent smell disorders in this population. Methodology: Consecutive patients consulting to the ENT department with post-Covid19 olfactory loss were included. The clinical examination included an analog scale for the self-assessment of olfactory recovery), a nasofibroscopy, the Sniffin’ Stick Test and the short version of the Questionnaire of olfactory disorders. Results: Among the 34 patients included, based on the Sniffin’ Sticks Test, 29.4% (n=10) could be classified as normosmic, 55.9% (n=19) as hyposmic and 14.7% (n=5) as functional anosmic). Only olfactory identification impairment was significantly correlated with olfactory complaint and daily anxiety and annoyance related to lack of olfaction recovery. This identification disorder seemed to worsen over time. Conclusions: It is crucial to assess odor identification disorders in case of persistent olfactory complaints after COVID-19. It is fundamental to target this disorder, as it does not improve spontaneously and negatively impact quality of life.

What about using sniffin’ sticks 12 items test to screen post-COVID-19 olfactory disorders?

“…The total SST-12, as SST, was significantly correlated ( p < 0.001) with odor complaint (VAS—Fig. 1 ) which reflects persistent post-COVID-19 olfactory impairment, i.e., mainly identification disorders rather than threshold or discrimination [ 2 ] as we published previously. Post-COVID-19 olfactory disorders show unique psychophysical characteristics consistent with a central olfactory impairment [ 2 , 15 ].…”

“…Screening for olfactory disorders is important because, in addition to allowing to set up appropriate care for patients, it helps prevent the occurrence of consequences of long-term anosmia, like an alteration in the quality of life [ 2 ], bad diet habits [ 3 ], changes in social relations [ 4 ], psychiatric disorders, such as depression [ 6 ], anxiety, or anorexia [ 7 ], its nutritional consequences [ 8 ], and finally cognitive impairment [ 4 ]. Although a subjective olfactory complaint (80% anosmia, 20% hyposmia) is now a very frequent symptom of a COVID-19 infection [ 32 ] affecting 70 to 85% of patients [ 33 , 34 ], only 21% of clinicians use psychophysical olfactory tests to characterize this olfactory complaint [ 35 ].…”

“…1 ) which reflects persistent post-COVID-19 olfactory impairment, i.e., mainly identification disorders rather than threshold or discrimination [ 2 ] as we published previously. Post-COVID-19 olfactory disorders show unique psychophysical characteristics consistent with a central olfactory impairment [ 2 , 15 ]. In a population of 34 patients deprived of their olfaction for about 6 months after COVID-19 and presenting a persistent odor complaint (VAS), we previously highlighted a significantly predominant, and gradually worsening, odor identification impairment [ 2 ], as Ianuzzi et al [ 20 ] underlined a lack of identification recovery in their 30 patients study.…”

“…The onset of a sudden partial (hyposmia) or total (anosmia) loss of smell is now recognized as highly predictive of SARS-COV-2 infection [ 1 ]. A long-lasting anosmia can lead to a quality of life [ 2 ] impairment, bad diet habits [ 3 ], changes in social relations [ 4 , 5 ] psychiatric disorders, such as depression [ 6 ], anxiety, or anorexia [ 7 ] and its nutritional consequences [ 8 ], and finally cognitive impairment [ 4 ]. Thus, olfactory disorders have to be diagnosed and managed especially as 12 [ 9 ] months after the COVID-19 infection, 30% of patients retain an olfactory complaint and require attention.…”

“…Seeing that it has been demonstrated that identification impairment is predominant in post-COVIDs [ 2 , 20 ], the objective of this study was to assess the potential value of SST-12 in screening and characterizing a persistent post-COVID-19 olfactory disorder in a daily practice.…”