A change in smell after COVID-19 infection: what you need to know

Sep 30, 2022 10:00 a.m.

University of Utah Health Communications

Information en español

Taste and smell are essential parts of enjoying everyday life. But for some COVID-19 long-haul carriers, these senses can become extremely off-putting. Some people experience a change in their taste and smell after COVID-19 infection, also known as parosmia (abnormal sense of smell), hyposmia (decreased sense of smell), and anosmia (loss of sense of smell). The good news is that it is usually only temporary, in most cases. However, no matter how long these conditions last, it can be very disruptive.

Kristine Smith, MD, a rhinologist and assistant professor in the Department of Otolaryngology (Head and Neck Surgery) at the University of Utah Health, answers eight questions about parosmia.

How is parosmia associated with COVID-19?

While it is not known exactly what causes parosmia, odor disturbance can be caused by viral illnesses such as the common cold or the flu. Head trauma, drugs, and neurological diseases such as Parkinson’s and other neurodegenerative diseases can also cause parosmia. During a viral illness, the nerve receptors in your nose can be damaged and your perception of smell can change. It is believed that this same phenomenon occurs during a COVID-19 infection.

How do COVID-19 long-haul carriers experience parosmia?

Loss of taste and smell is a common symptom of COVID-19 infection. In the recovery phase of COVID-19, a patient normally comes to his senses. However, some people experience a change in their sense of smell about three to four months after infection. People report that certain things, such as food or body odor, smell like garbage, rotten eggs, or chemicals. This altered sense of smell is called parosmia.

How common is parosmia?

The number of patients experiencing loss of smell and taste during or after COVID-19 infection varied widely. The loss or change of taste and smell during COVID-19 infection affects about 50-75 percent of people. About 25-75 percent develop parosmia in the recovery phase of COVID-19.

When will I get my sense of smell and taste back?

Patients usually improve slowly over time. About 65 percent of people with COVID-19-induced parosmia or hyposmia regain these senses after about 18 months, while 80-90 percent regain these senses after two years.

Who is more likely to develop parosmia?

If you lose your sense of smell or diminish your sense of smell while you have COVID-19, you are more likely to develop a disturbance in your sense of smell later on. But you can still experience parosmia even if you didn’t have a loss of smell originally. Patients who are younger and female also seem to have a higher incidence of experiencing post-COVID-19 odor disturbance. It is unclear why these groups are more affected.

Do people still experience parosmia with different COVID-19 variants?

The number of people reporting parosmia appears to change over time with COVID-19 variants. At the beginning of the pandemic, more cases of parosmia were reported with the original SARS-CoV-2 virus. While patients still experience parosmia, the number of patients seeking help with their symptoms is less with the newer variants.

Can parosmia be treated?

There are no guaranteed treatments for post-COVID-19 parosmia. However, some therapies may help some patients. Among which:

  • Olfactory Retraining is the process of retraining your nose to smell. It involves smelling strong scents (citrus, cloves, eucalyptus) every day while thinking about what they smell like to try to reshape the normal reactions on your nose and brain. Research has shown it can improve parosmia in long-term COVID patients. It often takes about 6 to 12 weeks to notice an effect and up to 24 weeks for maximum impact.
  • Intranasal Steroids (fluticasone or mometasone) are low-risk nasal spray therapies. Studies have shown that these therapies can improve the sense of smell in about 10-25 percent of patients.
  • High volume saline irrigations or sinus rinses (Neilmed, Netipot, Navage) help improve inflammation in the nose after an infection and may improve recovery after an infection.
  • Neuromodulatory Drugs change the way nerve cells transmit signals. Limited research has shown some improvements in olfactory dysfunction. These drugs, such as gabapentin and amitriptyline, are also used to control chronic pain or headaches. Because of side effects, they are usually used in patients with severe symptoms.
  • Lifestyle changes can help improve a patient’s quality of life, such as:
    • Eating simpler or bland meals: The more complex the aroma, the more likely it is to cause parosmia.
    • Food cold or at room temperature: Steam is what brings that sense of smell to your nose, which can cause parosmia.

Other therapies such as ganglion blocks, alpha-lipoic acid, and plasma-rich plasma (PRP) injection are under investigation as potential treatments for COVID-induced parosmia. The risks or potential benefits are not yet known.

Home or natural therapies are becoming more common, but DO NOT try these without talking to your doctor first. What you put in your nose can be absorbed into your bloodstream, potentially being dangerous to your health.

Can parosmia be dangerous to your health?

Losing your sense of smell or having a change in your sense of smell won’t directly harm you, but it can increase your risk of potentially harmful things.

Food poisoning
When your sense of smell returns incorrectly or is diminished for a long time, it can put you at risk of food poisoning because you may not be able to tell when something in your refrigerator has gone bad. People with parosmia should pay attention to expiration dates and label leftovers.

Smoke or natural gas
A person with parosmia may not be able to detect smoke or natural gas in their home. It is important to ensure that you have up-to-date smoke and natural gas detectors in your home. If you have a natural gas stove, consider purchasing a portable natural gas detector.

Mental health
The ability to smell and enjoy food is very important for our well-being. These kinds of changes can significantly affect a person’s quality of life. Having ongoing parosmia can potentially increase your risk of anxiety and depression. It is important to seek help to treat the associated problems.

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