Hyperosmia after COVID-19: hedonic perception or hypersensitivity?

Abstract

COVID-19 has been associated with a wide range of quantitative and qualitative disorders of smell, including hyposmia/anosmia, parosmia, and phantosmia; however, no reports to date have reported hyperosmia as a sequela of SARS-CoV-2 infection. We present two cases of subjective hyperosmia in a South Tyrolean Alps family, occurring within days after recovery from SARS-CoV-2 infection with transient anosmia. The subjects, a mother and son, exhibited subjective hyperosmia despite normal objective olfactory testing. During independent assessments, the severity of hyperosmia and specific odors affected were highly correlated, consistent with shared genetic and environmental factors. In contrast, two other family members with COVID-19 had no perceptual distortion and normal recovery of smell. Subjective hyperosmia after COVID-19 infection exhibited striking similarity in two affected family members, suggesting interaction of environment, genetics, and perception.