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Triggers for Post-Viral Parosmia

Triggers for Post-Viral Parosmia After COVID-19 and Non-COVID-19 Infections

Status
Completed
Phases
Unknown
Study type
Observational
Source
ClinicalTrials.gov
Registry ID
NCT04868435
Acronym
ParosmiaQ
Enrollment
943
Registered
2021-05-03
Start date
2020-11-03
Completion date
2023-02-03
Last updated
2023-05-09

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Parosmia, Smell Disorder

Keywords

Parosmia, COVID, Trigger foods

Brief summary

Background: Many people lose their sense of smell after they have had a cold, flu or sinus infection. Recovery (if at all) generally starts with a parosmia phase which means every-day smells become distorted and over-poweringly objectionable, and this can lead to malnutrition and depression. We do not know much about how or why parosmia happens, but there are key foods common to those who suffer from parosmia which seem to trigger the distortion. Parosmia and COVID-19 Loss of smell has recently been recognised as an official symptom of COVID-19, and we are starting to get reports of people who have recently had COVID-19 developing parosmia. The triggers seem to be similar to those of the common cold, flu or virus infections, but the journey between loss of smell and parosmia is different. Hypotheses 1. Triggers of distortion will be the same for all parosmics. 2. There may be additional trigger foods in different cultures. Questions 1. What are the trigger foods and beverages for parosmia? 2. Are there regional/cultural variations? 3. Does Covid-19 parosmia differ from standard post-viral parosmia? The overall aim of the project is to understand the mechanisms involved in parosmia. The approach is to identify foods and everyday aromas associated with parosmia and to determine whether they are the same across different continents/cultures/ethnic backgrounds, and whether Covid-19 parosmia is any different to non-Covid-19 parosmia. The questionnaire will ask about Covid-19 status, ethnic background, smell loss and parosmia, and the changes that occurred between smell loss and parosmia. The participants will then answer questions on up to 15 everyday smells, some of which our preliminary evidence shows are common triggers, and others which are not. The questionnaire will be globally distributed, for example through current collaborations in the UK, US, Germany, Iran, China, Japan and Brazil. It will be completed by participants who are currently experiencing parosmia. All participants will be asked to record any foods that they find distorted and provide a list of aromas which returned undistorted.

Detailed description

The questionnaire will be sent out to those reporting early stages of parosmia as a result of post-viral infection, including post-COVID-19 infection. The questionnaire will record demographic data and ask about COVID-19 status, COVID-19 diagnosis and results of COVID-19 tests. It will ask about loss of smell, taste and chemesthesis (irritation from the heat of spices) and it will ask about the sequence of events leading to parosmia. Up to 15 everyday items will be rated for aroma description, intensity and valence. Participants will be asked to list other distorted foods, and also smells that returned undistorted. The questionnaire will be fully anonymous (unlinked anonymous) and voluntary. The questionnaire will be designed, distributed and data collected using the secure platform provided by Compusense.

Interventions

None listed

Sponsors

AbScent
CollaboratorUNKNOWN
University of London
CollaboratorOTHER
University College London Hospitals
CollaboratorOTHER
University of Reading
Lead SponsorOTHER

Study design

Observational model
COHORT
Time perspective
PROSPECTIVE

Eligibility

Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No

Inclusion criteria

* Individuals should be currently experiencing parosmia

Exclusion criteria

* Individuals below 18 years old will be excluded from the study

Design outcomes

Primary

MeasureTime frameDescription
Questionnaire20 minutesOutcomes from the questionnaire will be: List of major trigger foods for anosmia. Typical descriptions for smell distortions. Severity of parosmia. Patterns of anosmia/parosmia symptoms in post-viral infections including Covid-19.

Countries

United Kingdom

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026