Loss of smell and COVID-19
Smell loss accompanied with taste loss is now a widely recognized presenting symptom of COVID-19 disease. This loss can happen suddenly without the appearance of any other nasal signs and is reversible in most cases. Smell loss is a safety issue and can affect an individual’s quality of life. People who lose their sense of smell may not be able to tell whether there is something burning in the kitchen or if there is a gas leak in their house. It is important for people who lose their sense of smell to make sure that their smoke detector is working properly. If there is propane or natural gas in the home, it is essential to get a propane or gas leak detector, which is different from a carbon monoxide detector.
The underlying mechanism of smell loss remains unclear. However, researchers from France have shed light on the mechanism of COVID-19-related smell loss according to a study published in Science Translational Medicine. They found that sensory neurons were infected with SARS-CoV-2 virus, which caused persistent inflammation in the olfactory system (sensory system used for smelling). Olfactory dysfunction generally lasts as long as the virus remains in the olfactory system.
The people most affected by smell and taste loss are young adults with mild to moderate COVID-19. In 80% of the individuals, this sensory loss returns to normal within 15 days. However, there are patients who take longer to recover. Fortunately, when the loss of smell persists, it is possible to recover the sense of smell with olfactory rehabilitation. This appears to be the safest method for recovery of the sense of smell. Other treatment categories include topical therapies, a variety of heterogeneous non‐steroidal oral medications, and acupuncture.
Olfactory rehabilitation includes practicing smelling. This makes it possible to regenerate the sense of smell more quickly. It consists of smelling items with recognizable smells bought at the grocery store, or by purchasing essential oils or a ‘fragrant lotto’. Initially, the fragrant lotto was a board game for children to allow them to enjoy discovering the fragrant substances hidden in small boxes. Individuals undertaking loss of smell rehabilitation smell three to five strong and recognizable odors every morning and night. They must smell each odor for 15 seconds with deep breaths through the nose and wait 10 seconds before smelling another odor. They must think about the scent and try to remember it by associating the corresponding word and image. The recommended odors are floral like rose, citrus like lemon, eucalyptus, and clove. Cleaning the nose regularly with saline water appears to improve the outcomes of this rehabilitation.
The magnitude of the importance of smell and taste becomes evident when people lose it. These people report feeling sad, depressed, or anxious. When this type of sensory dysfunction persists, it is advisable to visit a psychologist who will provide help to cope with this invisible disability.