Is It a Common Symptom?

It’s not uncommon for upper respiratory infections such as the common cold or flu to affect our senses of smell and taste. In fact, it’s estimated that a temporary loss of smell happens in over 60 percent of colds and sinus infections.

Your sense of taste and sense of smell are closely linked. In fact, experiencing a loss of smell can greatly impact your sense of taste. It’s estimated that 95 percent of the time when there’s a loss of taste, it’s associated with a reduced sense of smell.

Loss of smell can occur suddenly in people with COVID-19 and is often accompanied by loss of taste. Also, with COVID-19, these symptoms may occur without a runny or stuffy nose.

It’s possible that a loss of smell or taste could be an early symptom of COVID-19. A recent review evaluated eight studies with a total of 11,054 COVID-19 patients. According to this review, a loss of smell and taste often happened prior to other COVID-19 symptoms.

In particular, a loss of smell may also be a potential indicator of a mild case of COVID-19. A study from earlier in the pandemic found that loss of smell was more closely associated with outpatient care as opposed to hospital admission.

It’s still unclear exactly how a loss of smell and taste happens with COVID-19, but there are some theories.

SARS-CoV-2, the coronavirus that causes COVID-19, binds to a protein called ACE2 that’s found on the surface of potential host cells. ACE2 is abundant on cells found in your nose and mouth.

It’s possible that the virus could directly invade the nerve cells associated with your senses of smell and taste. However, a recent study in the journal Science Advances has cast doubt on this idea.

Researchers failed to find ACE2 on nerve cells that detect scents. Instead, they found ACE2 on cells that surround and support these nerve cells. It’s possible that infection of these surrounding cells could lead to levels of inflammation or damage that impact your ability to smell.

Less research has been done on how COVID-19 specifically affects taste. Since loss of smell and loss of taste often occur together, it’s currently believed that people with COVID-19 likely experience loss of taste as a consequence of loss of smell.

The reported prevalence of a loss of smell and taste with COVID-19 varies greatly across studies.

A recent study published in Mayo Clinic Proceedings took a deep dive into how common a loss of smell or taste is in COVID-19. Researchers reviewed results from 24 studies, which represented data from over 8,000 people with a confirmed case of COVID-19. They found the following:

• The reported prevalence for loss of smell ranged from 3.2 percent to 98.3 percent. The average prevalence of loss of smell was calculated to be about 41 percent.
• The reported prevalence for loss of taste was between 5.6 percent to 62.7 percent. The average prevalence for loss of taste was calculated to be about 38.2 percent.
• Older age correlated with a lower prevalence of loss of smell or taste.
• No difference in the prevalence of either symptom was seen in men versus women. However, other studies have found that loss of smell or taste tends to occur more frequently in women than in men.

Are you concerned that you may be losing your sense of smell or taste? If so, you can use common household items to test these senses.

Smell and taste test

• Smell. Find something that has a strong, characteristic smell. Foods may be a good option here, such as coffee beans, cinnamon, or fresh garlic. You can also choose to use non-food items like baby powder or a scented candle.
• Taste. Locate foods with different taste characteristics. Some good examples include things like chocolate (sweet), citrus (sour), coffee (bitter), and pretzels (salty).

If you find that you have trouble picking up on the scents or tastes of your selected items, you may be experiencing a loss of smell or taste.

If these symptoms developed suddenly, they could be an early indicator of COVID-19. If you’re concerned that you may have contracted the new coronavirus, you can seek out a testing site near you to confirm whether you have COVID-19.

Loss of smell or taste due to COVID-19 appears to last slightly longer compared to other upper respiratory infections. For example, loss of these senses due to a cold typically lasts for 3 to 7 days.

A report by the Centers for Disease Control and Prevention (CDC) assessed the duration of symptoms in 274 adults that had mild COVID-19 symptoms. The median reported duration of loss of smell or taste was 8 days.

This is supported by a smaller study from Europe. In this study, loss of smell and taste were strongly associated with each other, lasting an average of 8.9 days. For 98 percent of people, these symptoms cleared up within 28 days.

In addition to a loss of smell or taste, there are several other symptoms to watch out for with COVID-19. Some of the most common symptoms include:

If you believe that you may have COVID-19, stay home and try to isolate yourself from others in your household.

Contact your doctor to discuss your symptoms. Your doctor can also advise you on getting tested and how to care for yourself if you test positive for COVID-19.

Most of the time, mild cases of COVID-19 can be treated at home. However, in some cases the illness can become more serious. This is more likely in older adults and in individuals with certain underlying health conditions, such as:

Seek emergency medical care immediately if you experience:

• difficulty breathing
• chest pain or pressure that doesn’t go away
• lips, face, or fingernails that are blue in color
• confusion
• trouble staying awake or difficulty waking up

In addition to COVID-19, there are many other factors that can cause you to lose your sense of smell or taste. These can include:

• smoking
• other upper respiratory infections, such as colds, the flu, or sinus infections
• allergies
• nasal polyps
• a head injury
• neurological conditions, including Parkinson’s disease, multiple sclerosis, and Alzheimer’s disease
• medications, such as some types of blood pressure medications, antibiotics, or antihistamines
• hormonal changes due to conditions like hypothyroidism or Cushing’s syndrome
• surgeries impacting the mouth, nose, or throat, such as sinus surgery or removal of wisdom teeth
• radiation treatment for cancers in the head or neck
• tumors in or around the head and neck
• being exposed to some types of chemicals or solvents

A loss of smell or taste can happen with COVID-19. These symptoms often occur together, although they can they can also occur separately.

With COVID-19, a loss of taste or smell can come on suddenly and occur early, sometimes before other COVID-19 symptoms develop. Unlike other upper respiratory infections, a loss of smell or taste isn’t always associated with a runny or stuffy nose.

Most people who experience loss of smell or taste due to COVID-19 find that these symptoms resolve within a few weeks.

Although COVID-19 is mild most of the time, it can escalate to a serious illness. Seek emergency medical care if you have symptoms such as difficulty breathing, chest pain, or confusion.