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Is Loss of Smell a Symptom of COVID-19?

Published on Apr 01, 2020 and last reviewed on Jan 05, 2021   -  5 min read

Abstract

Doctors have noted that coronavirus (COVID-19) patients exhibit loss of taste much before they develop cough, fever, and breathing problems. Read the article to know more.

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Is Loss of Smell a Symptom of COVID-19?

Is Loss of Smell a Symptom of COVID-19?

According to the World Health Organization (WHO), the symptoms of novel coronavirus disease (COVID-19) so far are a dry cough, fever, and dyspnea (shortness of breath). But, there is a lot of evidence emerging from countries that are currently battling this virus, that sudden loss of smell and sometimes, even taste, can be symptoms. This has made scientists and researchers wonder if this is an early sign of the new deadly coronavirus. Even though these symptoms have not been included officially, there are various reports and articles talking about them. Then why is everybody talking about it? Read on to find out.

A significant number of coronavirus patients in South Korea, China, and Italy have developed anosmia (loss of smell), ageusia (loss of taste), and hyposmia (reduced ability to smell). The British Association of Otorhinolaryngology stated in an online post that a large number of coronavirus infected patients who did not show any other symptoms had a loss of taste and smell. Statistics show that there is a sudden rise in cases of partial or total loss of smell in the UK, France, the US, and Italy. But as these patients do not fit any other criteria for COVID-19 testing, they could not confirm that these are the symptoms of early coronavirus infection.

Why Are People Reporting a Loss of Taste Along With Smell?

It is important to note that we smell and taste food together when we eat. If you pinch your nose and then eat, you will notice that the only things you can perceive are if the food is salty, sour, sweet, savory, and bitter, as these elements come from the taste buds present on the tongue. You will not exactly be able to appreciate the essence and flavor of what you are eating. This is why most people who lose the sense of smell also think that their sense of taste is lost.

The other strains of coronaviruses, that resulted in SARS and MERS, were also responsible for causing 10 to 15 % of anosmia cases, which is why researchers are not surprised that the novel COVID-19 virus can also result in similar symptoms.

How Is the Sense of Smell Affected?

The viruses that cause common colds and the flu result in nasal congestion, nasal obstruction, edema of the nasal mucosa, and excess nasal secretions, which can lead to loss of smell. Microscopically, the nasal tissues can be seen to have fine hair-like endings. These cells pick up odor molecules from the nose and carry it to your brain. In such infections, these receptor cells fall off, hence the symptom.

Loss of smell and taste due to a viral infection usually is temporary, and the patient regains these senses once he or she recovers. Only around 1 % of patients suffer from persistent anosmia and ageusia.

Initial testing on the COVID-19 shows that it has a high concentration in the nose. It is believed that the virus affects the sense of smell by inflammation of the olfactory nerves, rather than affecting the receptor cells in the nose. The long term effect of this has still not been documented.

What to Do If You Experience Smell or Taste Loss?

Even though the current guidelines on self-isolation for COVID-19 does not include anosmia and ageusia as symptoms, if you feel you might have contracted the virus in the past couple of weeks, you should self-isolate. And wait and watch for any other symptoms for the next 14 days. Also, ask your family members to stay at home for 2 weeks.

Avoid using oral steroids to treat these symptoms, as it is believed that oral steroids can exacerbate the underlying viral infection. You may use nasal steroids after consulting a doctor first.

COVID-19 Patients and Damaged Sense of Smell (Parosmia):

Many recovered COVID-19 patients are now reporting that certain food items smell and taste awful. This temporary condition that distorts odors, making them unpleasant, is called parosmia. While the patient can at least smell something after a complete loss of smell and taste, it indicates that these senses are returning. But, parosmia can last for long periods and can make foods like coffee, eggs, fried foods, and chocolate intolerable. Some patients also report smelling odors that are not there, like sewage, rotten food, and cigarette smoke. This distortion is called phantosmia.

This can be frustrating for recovering patients, as the food they once loved might smell revolting. A report published by the Global Consortium for Chemosensory Research stated that out of 4,000 COVID-19 patients, 7% had a distortion in their sense of smell. But this finding is not surprising as parosmia and phantosmia usually occur after viral infections. Doctors believe that parosmia due to COVID-19 is actually a good sign because it indicates that your olfactory tissues are regenerating and returning to normal.

What Should Doctors Do?

As anosmia has been commonly seen in patients who get ultimately tested positive and are otherwise asymptomatic, it is wise to include this in the early symptoms of coronavirus.

If your patient complains of anosmia and ageusia, and-

Then the best thing to do would be to test the patient for the virus. But with the present guidelines and lack of testing kits, testing is only done if the patient has a fever, cough, and shortness of breath. So, advise the patient to self-isolate for at least 14 days, and to report back in case he or she develops shortness of breath or fever.

The need of the hour is for more testing kits to be available for COVID-19. This is the only definite way to know whether anosmia and dysgeusia are indeed symptoms of this disease or an incidental finding.

How Common Are Anosmia and Ageusia Reported as Symptoms of COVID-19?

As of 29th March 2020, there are 722, 088 confirmed cases of COVID-19 in the world. In Germany, two out of three confirmed cases experienced a loss of smell, and in South Korea, these symptoms were reported in 30 % of all patients who tested positive.

The thing to remember is, most of this evidence is anecdotal for now. But with the number of reported cases at a rise, medical professionals are urging for anosmia and ageusia to be considered symptoms of COVID-19.

If Not COVID-19, What Are the Other Causes of Anosmia?

If you are experiencing a loss of smell, we do not want you to jump to any conclusions. The relationship between COVID-19 and anosmia is still to be confirmed by experts. But the following are some of the established causes of anosmia:

  1. Nasal Mucous Membrane Irritation:

    1. Sinusitis.

    2. The common cold.

    3. The flu.

    4. Allergic rhinitis.

    5. Smoking.

  2. Nasal Passages Blockage:

    1. Nasal tumors and polyps.

    2. Deviated nasal septum.

  3. Brain or Nerve Disorders or Damage:

    1. Aging.

    2. Head injury.

    3. Hormonal imbalance.

    4. Medications such as antibiotics and antihypertensives.

    5. Alzheimer’s.

    6. Brain tumors.

    7. Multiple sclerosis.

    8. Parkinson’s.

    9. Epilepsy.

    10. Brain surgery.

    11. Stroke.

    12. Schizophrenia.

    13. Diabetes.

    14. Congenital anosmia (babies born without the sense of smell)

    15. Chemical injury to the nose.

    16. Malnutrition.

    17. Radiotherapy.

    18. Alcoholism.

Can Anosmia Be Treated?

If the cause of anosmia is a cold, sinus infection, or allergy, it usually gets better on its own in a few days. In case it does not, then it is better to consult a doctor. The doctor might prescribe decongestants, antihistamines, steroid nasal sprays, or antibiotics (if it is a bacteria infection).

If the cause is nasal obstruction, then the doctor will perform a procedure to straighten the nasal septum or remove nasal polyps.

Loss of smell seen in older people and people with congenital anosmia is unfortunately permanent and cannot be cured.

There are a lot of myths and fake news surrounding the spread and symptoms of the new coronavirus, so do not believe and act on those without confirming it by a doctor online. Stay home and be safe!

 

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Last reviewed at:
05 Jan 2021  -  5 min read

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