Loss of smell in mild Covid-19 cases occurs 86% of the time, study says

Some 86% of people with mild cases of Covid-19 lose their sense of smell and taste but recover it within six months, according to a new study of over 2,500 patients from 18 European hospitals.(Lechien et al. n.d.)

[ A case of Covid-19 was considered mild if there was no evidence of viral pneumonia or loss of oxygen and the patient was able to recover at home]

This could be anyone…

And worse.. The sense of smell reappeared after an average of 18 to 21 days, the study found, but about 5% of people had not recovered olfactory function at six months.

Anosmia, which is a loss of smell, and therefore taste, has been suggested as an early sign of Covid-19. It can occur without any prior warning, not even a stuffy nose.(Gautier and Ravussin 2020)

“Anosmia, in particular, has been seen in patients ultimately testing positive for the coronavirus with no other symptoms,” according to the American Academy of Otolaryngology-Head and Neck Surgery.(139939 2020)

Moderate to Severe Covid-19

Comparatively, the study found that only 4% to 7% of people with moderate to severe symptoms of Covid-19 lost their ability to smell and taste. (Lechien et al. n.d.)

People with moderate Covid‐19 had “clinical signs of pneumonia,” the study said, such as cough, fever and difficulty breathing. Those with critical cases of the disease suffered severe respiratory distress, and were more likely to be older and have “hypertension, diabetes, gastric disorders, renal, respiratory, heart, liver and neurological disorders.”

The study, which published Monday in the Journal of Internal Medicine, found a higher rate of olfactory dysfunction in younger patients compared to the elderly, but that association needs further analysis, the researchers said. (Lechien et al. n.d.)

Smell loss is common BUT What about RECOVERY?

Of course, not everyone who flunks a smell test is going to have coronavirus. Any respiratory virus, such as cold or flu, will temporarily impact smell and taste, sometimes even permanently.

That means that they harm the olfactory nerve and it becomes essentially nonfunctional,” he added. “Many of those cases can recover smell with time, but sometimes it’s a permanent loss.”

A partial or complete chronic loss of smell is incredibly common, Munger said, affecting millions of Americans long before the novel coronavirus burst upon the scene.

“About 13% of the population has a significant smell or taste impairment,” he said.

Besides cold and flu, other causes of smell loss include nasal polyps, tumors, neurodegenerative diseases like Alzheimer’s or Parkinson’s, and traumatic brain injury or head trauma, including whiplash.

“If someone has been in an auto accident or had a whiplash injury or head injury, that could also impact the little nerves as they go from the brain down to the nose,” Voigt said. “So a whiplash injury could also cause a permanent loss of sense of smell.”

A loss of taste is commonly associated with the loss of smell, because we rely on smell to identify flavors. But there can also be medical reasons: Some medications can affect taste; chemotherapy and radiation therapy can certainly disrupt taste; and then there is physical damage, such as nerves severed during dental surgeries.

My gosh . . .

Different underlying mechanisms have been advocated to explain the presence of anosmia in patients with COVID-19. These include olfactory cleft syndrome, direct damage of olfactory sensory neurons, postviral anosmia syndrome, cytokine storm, and/or impairment of the olfactory perception centers in the brain. (Saussez, Lechien, and Hopkins 2020)

Anosmia is associated with depression, loss of appetite, and diminished quality of life, but it’s also an invisible and underappreciated phenomenon.(Elkholi, Abdelwahab, and Abdelhafeez 2021)

parosmia

n. A distortion of the sense of smell, as in smelling odors that are not present.

n. In pathology, a perversion of the sense of smell; olfactory illusion.

n. A distorted sense of smell, often resulting in phantom, non-existent, and mostly unpleasant, smells.

Complete recovery of smell function after a mean follow up of 229 days was found in 52% of patients, while 48% reported only partial recovery. (Biadsee et al. 2020)

Olfactory and/or gustatory dysfunction have been widely reported as one of the sole initial manifestations of COVID-19 infection.(Kaye et al. 2020) (Paderno et al. 2020)

Several therapies such as zinc, intranasal corticoid injections and systemic steroids have been used in post-viral OD, but have never proven to be effective [22]. (Hura et al. 2020)

To date, the only approved treatment is daily and long-term olfactory rehabilitation, which could improve the olfactory capacities of patients up to 30% [23]. (Hummel et al. 2009)

However, whether olfactory rehabilitation could be effective in COVID-19 patients with anosmia still remains to be demonstrated.(Cousyn et al. 2021)

As such, based on our current understanding of the available evidence, there may be additional risk associated with systemic steroid therapy for the treatment of COVID-19.(Hura et al. 2020)

Recent research has shown that Transcranial Photobiomodulation Therapy [tPBMT] was able to restore the sense of smell as her cognitive scores improved from dementia to normal. (Salehpour, Hamblin, and DiDuro 2019). To date this was the first time in the literature that one’s sense of smell was restored in a neurodegenerative condition. The use of transcranial and intranasal photobiomodulation tPBMT was an integral part of the clients care plan. We know that this therapy increases blood flow to the nasal area and olfactory nerves and may have an antiviral, anti-inflammatory and anti-aging effect also. (Salehpour et al. 2020)

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Biadsee, Ameen, Ameer Biadsee, Firas Kassem, Or Dagan, Shchada Masarwa, and Zeev Ormianer. 2020. “Olfactory and Oral Manifestations of COVID-19: Sex-Related Symptoms — A Potential Pathway to Early Diagnosis.” Otolaryngology–Head and Neck Surgery 163(4):722–28. doi: 10.1177/0194599820934380.

CNN, Sandee LaMotte. n.d. “Loss of Smell in Mild Covid-19 Cases Occurs 86% of the Time, Study Says.” CNN. Retrieved May 4, 2021 (https://www.cnn.com/2021/01/06/health/loss-of-smell-covid-study-wellness/index.html).

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Hummel, Thomas, Karo Rissom, Jens Reden, Aantje Hähner, Mark Weidenbecher, and Karl-Bernd Hüttenbrink. 2009. “Effects of Olfactory Training in Patients with Olfactory Loss.” The Laryngoscope 119(3):496–99. doi: https://doi.org/10.1002/lary.20101.

Hura, Nanki, Deborah X. Xie, Garret W. Choby, Rodney J. Schlosser, Cinthia P. Orlov, Stella M. Seal, and Nicholas R. Rowan. 2020. “Treatment of Post-Viral Olfactory Dysfunction: An Evidence-Based Review with Recommendations.” International Forum of Allergy & Rhinology 10(9):1065–86. doi: https://doi.org/10.1002/alr.22624.

Kaye, Rachel, C. W. David Chang, Ken Kazahaya, Jean Brereton, and James C. Denneny. 2020. “COVID-19 Anosmia Reporting Tool: Initial Findings.” Otolaryngology–Head and Neck Surgery 163(1):132–34. doi: 10.1177/0194599820922992.

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