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Parosmia and Phantosmia: Olfactory Disorders You Should Know About

Written by Dan Navarro · Updated Aug 06, 2021

    Parosmia and Phantosmia: Olfactory Disorders You Should Know About

    When we talk about olfactory or smelling disorders, loss of smell usually comes to our minds. Depending on the severity, we may experience partial (also known as hyposmia) or complete (also known as anosmia) loss of smell. While both are usual symptoms of a sinus infection or common cold, people are more aware of anosmia as it has been one of the recognized symptoms of COVID-19. Yet, other studies also suggest that hyposmia may also be a good indicator of virus infection. However, in other instances, people may also experience two less-known kinds of smelling disorders: parosmia and phantosmia.

    Parosmia refers to the experience of detecting a distorted, unpleasant smell from an object that has a rather pleasant scent. On the other hand, phatosmia refers to the experience of perceiving a hallucinated odor, something that is not present in your surroundings at the moment.

    What more do we need to know about these olfactory disorders? Are these as serious as having a loss of smell? What’s their relation with COVID-19? How should these disorders be treated?

    Parosmia and Phantosmia: What’s the Difference?

    Healthcare practitioners classify both parosmia and phantosmia as qualitative olfactory disorders, setting them apart from the quantitative smelling disorders such as anosmia and hyposmia. 

    How do parosmia and phantosmia differ? Simply put, parosmia is an altered perception of smell towards an object. And phantosmia is the detection and perception of an odor from something that does not exist within the surroundings at the time.

    People may experience parosmia by detecting an unpleasant smell from things that have a pleasant scent, such as food items that smell sweet or enticing. It may result in the avoidance of food items and even weight loss. However, some experts have studied a rare form of parosmia called euosmia that involves detecting a pleasant scent. 

    On the other hand, people with phantosmia may perceive a smell from a non-existing source around them during that time. For instance, they may detect an odor from recognizable objects that are not within a room or any other immediate surroundings. Under this condition is cacosmia, a form of phantosmia that perceives an unpleasant smell from a non-existing object around one’s area.

    Causes of Parosmia and Phantosmia

    Studies about parosmia and phantosmia are limited, and doctors have yet to reach a consensus on the causes of these qualitative smelling disorders. However, experts have attempted to look at how the two are acquired. 

    Some of these causes of parosmia and ohantosmia include the following:

    1. Viral upper-respiratory infections
    2. Damages in olfactory nerve receptors. 
    3. Injuries in parts of the olfactory system;
    4. Post-Traumatic Olfactory Loss;
    5. Exposure to toxins;
    6. Neurological disorders such as epilepsy, Parkinson’s, and Alzheimer’s diseases.

    COVID-19 and Loss of Smell

    One of the known indicators of COVID-19 infection is the loss of smell. Studies have shown that the virus is commonly associated with anosmia or the complete loss of olfactory senses. Although, some also looked through the correlation between the virus and hyposmia or the partial loss of smell. However, other studies have looked into the correlation of COVID-19 infections to parosmia and phantosmia.

    For instance, a 2021 study that involved 268 Iraqi COVID-19 patients with parosmia revealed that before having the said olfactory disorder, 241 had previously experienced anosmia, while the rest had hyposmia. Most cases experienced an unpleasant smell, with 146 patients saying that the odor was similar to that of sewage. In addition, 91.8% of cases experienced a loss of appetite, decreased weight, and mood changes.

    Phantosmia, on the other hand, is not commonly associated with COVID-19. Few studies have attempted to look into the condition relative to the virus but concluded that there’s little to no correlation. One study, for instance, revealed that prevalence of phantosmia, while slightly higher in COVID-19-negative respondents, are equally occurring in those who tested positive and negative positive for the virus. However, they suggested that phantosmia can be triggered more by rhinosinusitis.

    In conclusion, studies suggest that parosmia is more prevalent in post-COVID-19 infection after the manifestations of anosmia and hyposmia. Meanwhile, there is no correlation between phantosmia and COVID-19. 

    Treating Parosmia and Phantosmia 

    Fortunately, recovery from parosmia and phantosmia is possible and should take a few weeks. There are also ways to treat these olfactory disorders through the following:

    • Valsalva Maneuver. It involves exhalation but with the mouth closed and nose pinched.
    • Head Movements. Moving the head in different positions may also be helpful when symptoms of parosmia and phantosmia manifest.
  • Smell Training. This treatment involves a daily routine of smelling items with different odors. The idea is that training your olfactory senses to smell scents may help to regain your sense of smell. Various studies have supported this routine, including a journal article published last year on The Laryngoscope.
    • Consult a professional. For prolonged cases, especially those whose quality of life is decreasing, it is vital to seek help from a professional, such as an Ear, Nose, and Throat (ENT) doctor.

    Key Takeaways

    Parosmia and phantosmia are qualitative olfactory disorders that can still affect one’s quality of life. These disorders involve perceiving unwanted scents from nearby or non-existing items in your area that may lead to mood changes, loss of appetite, and even a drop in weight. While these go away after a few weeks, there are treatments and routines to mitigate or fully recover from such disorders. However, for prolonged cases, consult a professional to seek the best way to recover from the said disorders.

    Learn more about Nose Conditions here.


    Hello Health Group does not provide medical advice, diagnosis or treatment.

    Written by Dan Navarro · Updated Aug 06, 2021

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