86% of COVID-19 patients may have smell abnormalities

86% of COVID-19 patients may have smell abnormalities

Last Reviewed : 12/15/2020
86% of COVID-19 patients may have smell abnormalities

The most prevalent symptoms of COVID-19 identified so far include fever, cough, fatigue, sputum production, shortness of breath, body aches, sore throat, headache, nausea, vomiting and diarrhea. Research studies from China did not report smell or taste abnormalities as one of the symptoms. As COVID-19 spread rampantly to Europe and the United States, more clinical features are being associated with COVID-19.

Smell abnormalities due to viral infections are commonly seen as there are associated runny nose, and congestion. Viruses like rhinovirus, parainfluenza, and respiratory syncytial virus are known to cause smell abnormalities. However, it is interesting to note that smell abnormalities in COVID-19 infection are not associated with a runny nose or nasal obstruction.

According to a large study published in European archives of oto-rhino-laryngology, 417 patients from 12 European hospitals were administered a questionnaire regarding their smell and taste symptoms. 86% of the patients had smell abnormalities. While 68% of the total patients lost smell completely, 17.5% of the patients had reduced smell. Recovery from smell abnormalities occurred later in the course of illness after other symptoms resolved.

89% of the studied patients reported taste disorder. The majority of these patients had reduced taste and some had distorted ability to taste.

The study also reported the general treatments used for smell and taste disorders. Nasal irrigation, nasal steroids, oral steroids and decongestants were used to treat smell disorders. L-carnitine, vitamins and minerals were used to treat taste disorders.

Smell disorder may be seen before any other COVID-19 symptoms appear in about 12% of the patients. The rest of the patients may have smell disorder during or after other COVID-19 symptoms develop.

Reduced or loss of smell is identified in 80% of the patients without runny nose or nasal blockage. This differentiates COVID-19 from other viral upper respiratory infections where smell disorders are usually seen in associated with runny nose and nasal blockage. The exact mechanism is not clear but it is thought that COVID-19 affects peripheral nerves in the nasal cavities resulting in reduced or absent smell.

Similar to this study, other published data reported 2/3 of patients in Germany to have absent smell. Numbers from South Korea indicate that 30% of COVID-19 patients had absent smell (anosmia) as the primary presenting symptom.

These published data sheds light on smell and taste disorders as some of the most common symptoms associated with COVID-19. During this pandemic, individuals presenting with sudden onset of absent or reduced smell without other symptoms should be considered testing for COVID-19. ENT doctors all across the globe may see few COVID-19 patients in their clinics who may not have other classic symptoms like fever, cough, body aches, or shortness of breath.




  • Clinical Characteristics of Coronavirus Disease 2019 in China. Wei-jie Guan et al. New England Journal of Medicine. February 28, 2020. DOI: 10.1056/NEJMoa2002032
  • A review of the 2019 Novel Coronavirus (COVID-19) based on current evidence. Wang LS et al. Int J Antimicrob Agents. 2020 Mar 19:105948. doi: 10.1016/j.ijantimicag.2020.105948.
  • Lechien JR. Olfactory and gustatory dysfunctions as a clinical presentation of mild-to-moderate forms of the coronavirus disease (COVID-19): a multicenter European study. Eur Arch Otorhinolaryngol. 2020 Apr 6. doi: 10.1007/s00405-020-05965-1.
  • Gautier JF et al. A New Symptom of COVID-19: Loss of Taste and Smell. Obesity (Silver Spring). 2020 Apr 1. doi: 10.1002/oby.22809.

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