COVID-19: Loss of smell may be followed by smell distortions

Many people who lose their sense of smell due to COVID-19 eventually regain it, but some survivors later report smell distortions and unexplained smells, a new study found.

Researchers analyzed survey responses from 1,468 individuals who had been diagnosed with COVID-19 between April and September 2020 and had suffered loss of smell and taste at the start of their illness. Early on, about 10% also reported smell distortions, or parosmia, and unexplained smells, known as phantosmia.

At an average of six to seven months after becoming ill and first reporting loss of smell, roughly 60% of women and 48% of men had regained less than 80% of their pre-illness smell ability, and rates of smell distortions and imaginary smells had increased, the researchers reported on Tuesday on medRxiv ahead of peer review.

Roughly 47% reported parosmia, saying, for example, “some things now smell like chemicals.” About 25% reported phantosmia.

“Sometimes I can smell burning but no one else around me can,” one respondent reported. Persistent smell problems were seen more often in survivors with more symptoms overall, “suggesting it may be a key marker of long-COVID,” the authors said.