COVID-19 and Smell Disorders: Parosmia and Phantosmia
COVID-19 can affect the sense of smell, leading to a variety of symptoms, including smell loss, parosmia, and phantosmia.
Smell Loss
Smell loss, or anosmia, is a common symptom of COVID-19, affecting up to 86% of patients. Most people recover their sense of smell within a few weeks, but some may experience persistent smell loss.
Parosmia
Parosmia is a distortion of the sense of smell, making things smell unpleasant or even revolting. It is a common symptom of COVID-19, affecting approximately 7% of patients. Triggers for parosmia can include foods such as coffee, chocolate, and red wine.
Phantosmia
Phantosmia is a condition in which people experience smells that are not present in the environment. These smells can be fleeting or linger for extended periods and are often unpleasant, such as cigarette smoke or burning wood.
Causes of Smell Disorders in COVID-19
The SARS-CoV-2 virus, which causes COVID-19, can damage the olfactory neurons responsible for transmitting smell information to the brain. It can also damage the supporting cells that surround these neurons, impairing their function. Additionally, inflammation caused by the virus can disrupt nerve function, contributing to smell disorders.
Recovery from Smell Disorders
Regeneration of olfactory neurons is possible after damage, but it can take time, up to two years or more. During recovery, patients may experience parosmia as the olfactory system gradually recovers.
Triggers for Parosmia and Phantosmia
Certain foods and smells can trigger parosmia and phantosmia in COVID-19 patients. Common triggers include:
- Gasoline
- Tobacco
- Coffee
- Perfumes
- Chocolate
- Vegetable oil (e.g., tortilla chips, french fries)
Treatment for Smell Disorders
Currently, there is no definitive treatment for smell disorders associated with COVID-19. However, ongoing research is investigating various approaches, including:
- Fish oil supplements
- Transcranial stimulation
- Olfactory retraining exercises
Impact of Smell Disorders on Quality of Life
Smell disorders can significantly impact quality of life, affecting enjoyment of food, social interactions, and emotional well-being. Patients may experience anxiety, depression, and social isolation due to their altered sense of smell.
Ongoing Research
The prevalence of smell disorders in COVID-19 has spurred increased research in the field of chemosensory sciences. Global collaborations are investigating the connection between the chemical senses and COVID-19, exploring new treatments and strategies for recovery.