Anosmia is a condition that describes the failure of our sense of smell. Although there are many other conditions that can cause anosmia, it had become well-known since the pandemic started, as it was classified as one of three typical symptoms of COVID-19 before people were vaccinated.
Loss of sense of smell occurs during the acute COVID illness but can last long after you have since recovered. Your ability to smell is closely linked to your taste buds, so it can make your food taste bland or alter your smell so that things either don’t smell like anything or smell very different. You may detect a charred or burning smell, and this can have a negative effect on your appetite.
You may only be able to smell or taste a little – partial anosmia – or you may find certain smells or tastes unpleasant. You may experience a bad smell all the time, like smelling smoke or petrol, even if it’s not present.
Unlike most other viruses that cause nasal congestion or inflammation, COVID-19 crosses the blood-brain barrier, entering the nervous system and affecting the neural connections that detect and process smells, known as your olfactory system.
COVID-19 affects everybody differently; it is, therefore, difficult to predict how long anosmia may affect you. Some recover within a week, while for others, it can take them several months or even longer. For a few, the sense of smell may not return.
Many find they experience distorted smells as the sense returns or imagine smells that aren’t there, a phenomenon known as phantosmia or olfactory hallucination, which can be distressing if they are unpleasant smells, but it a sign of the nerves regenerating.
The majority of people will gradually regain their smell. Research shows that 90% of people had fully recovered within six months. Still, it can take up to 18 months to regenerate olfactory cells, depending on where the olfactory system has been damaged, and for some, it will, unfortunately, be permanent damage.
Research is ongoing as to whether surgical techniques may prove effective. In the meantime, the mainstay of treatment is smell retraining therapy, a short course of steroid tablets or steroid nasal spray that your doctor can prescribe, or zinc and vitamin A supplements, which you can buy from a pharmacy. The retraining therapy has had reasonable results, but there is a mixed success with the other methods.
Smell retraining therapy works by slowly reintroducing yourself to distinct smells in the hope that it can stimulate the olfactory system in the brain to remember how to smell. The four categories that are advised to retrain are floral, such as rose, fruity, like orange, spicy, like cloves, and a category called resinous, which eucalyptus fits into.
The retraining technique involves taking gentle sniffs of each scent in order, for 20 seconds at a time, twice a day, and concentrating on the memory of that smell. This should be done for at least 3 months.
Community-based support may be available in your area. Learn more at the Administration for Community Living.
There are safety implications if you can't smell burning or gas leaks, so ensure you have smoke alarms at home and work and test them regularly. If you have a gas oven or furnace, buy some gas sensors in case there's a leak. Ensure household members and co-workers are aware that you will not be able to smell any danger so that they can be more vigilant.
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