The sense of smell is undoubtedly the least known… and respected sense. If the Covid-19 epidemic has focused on this sense, or rather on anosmia, being a symptom that allows us to differentiate it from the flu, there are other pathologies that can deprive this sense. We know even better the methods to improve our sense of smell from this global pandemic. Decryption with two experts, Dr. Jérôme Lechien, ENT atthe Foch hospital (in Suresnes) and Jean-Michel Maillardanosmic patient and founder of the association anosmia.org.
Covid, cold, accidents… What can be the causes of anosmia or hyposmia?
It is necessary to differentiate the acute loss of smell, which lasts a few weeks, from the chronic loss of smell. And the total anosmia of hyposmia, that is to say a great difficulty in finding smells.
- The most common cause of short-term anosmia is infectious diseases: rhinitis, nasopharyngitis, Covid-19. “Patients have a blocked nose, odors are no longer able to reach the olfactory fissure, the highest part of the nose,” he describes. Jérôme Lechien, ENT at the Foch hospital and in Belgium. But it resolves in 2 or 3 weeks!
More serious and disabling, some complain of a loss of smell for months, years… In this case, the causes can be different:
- Chronic rhinosinusitis with polyps
“We noticed a type of buds, small benign tumors in the nasal mucosa, which obstruct the olfactory slits, continues the doctor. Odors are captured by the upper part of the nose which is 1 millimeter thick, as soon as it swells. close access to odor receptors.”
Allergies can also cause a completely blocked nose, which can result in a partial loss of smell. “In these two cases, these are common causes that can be easily treated,” reassures the ENT specialist.
On the other hand, it can happen that the patient complains of long and complete anosmia even if the ORL examination is normal. If the nose examination reveals neither polyps nor sinusitis, there are 3 possible causes:
- Post-viral loss of smell
“A bad sinusitis or Covid-19 can destroy the receptors of the smell, explains the doctor. Why it lasts for years in some patients we do not know, but we have a hypothesis that the immune system destroys the cells trying to regenerate”.
It is more rare, but after an accident, a fall for example, the injury can sever branches of the olfactory nerve and thus make the person anosmic.
“In Parkinson’s or Alzheimer’s disease, the loss of smell can be a precursor symptom that can occur 10 years before these diseases,” reveals Jérôme Lechien. This is a sign that some neurons are starting to be destroyed.
Are there treatments to recover your sense of smell?
Obviously, it depends on the underlying cause. If it is a simple rhinitis, the sense of smell may return without action on your part. If there are polyps, they probably need to be removed.
For chronic loss of smell that cannot be explained by these physical causes, it is advisable to carry out olfactory rehabilitation.
Finally, and this is very recently, a new treatment has been developed and seems to be effective in helping anosmics to recover their sense of smell. His nickname? The PRP, for platelet-rich plasma. Jérôme Lechien offers them Saint-Pierre University Hospital of Brussels. “We take a blood sample, centrifuge it and keep only the platelets, because it is a growth concentrate,” he describes. A process that is also used in other pathologies, for example for tendinitis or arthrosis. Except here, we’re going to reinject this PRP into the nose. “There will be 2 mechanisms: an anti-inflammatory effect that prevents the immune system from destroying the regenerating cell. Second consequence: accelerate the regeneration of olfactory cells by 10 to 20 times. In 80% of cases, people recover. u his sense of smell where there had been no development for many years! If this treatment is offered routinely in the United States and for 2 and a half years in Belgium, this is not the case in France. some hospitals, especially in Marseille and Nantes, are studying this new treatment, but in a research context and not on a routine basis.