Résumé
The Covid-19 pandemic marked the 21st century! and SARS-CoV-2 is associated with a high prevalence of smell disorders, which are frequently sudden-onset anosmia. In addition, post-viral infection dysosmia was known. However, Covid-19-related dysosmia is distinguished by a slower prognosis for recovery of the sense of smell and a higher prevalence of olfactory disorders than other viral aetiologies. Indeed, the prevalence of dysosmia was estimated at between 48 and 61% during the circulation of the Alpha and Delta variants, both of which have the D614G mutation. Later, the appearance of the Omicron variant reduced the prevalence of smell disorders to 15%. Moreover, 2 years after infection, around 5% of patients with Covid-19-related olfaction disorders still suffer from them, and olfactory sequelae such as parosmia often follow anosmia in the case of long Covid. The mechanisms governing the acute phase of olfactory disorders and the events leading to prolonged olfactory problems have given rise to a great deal of excitement in the world of research. Numerous studies are attempting to unveil the pathophysiology of odour disorders linked to Covid-19. The olfactory epithelium has been at the heart of research because the virus can be detected up to two years after infection. Prolonged inflammation of the epithelium is thought to be linked to the persistent presence of the virus, leading to olfactory disorders. However, other hypotheses currently being studied seem plausible and may coexist with prolonged inflammation of the olfactory epithelium. The advent of SARS-CoV-2 is encouraging healthcare professionals and patients alike to find therapeutic solutions to smell disorders. This is why olfactory rehabilitation appears to be the best option to date, offering particularly satisfactory results when carried out with essential oils. Aromatherapy plays a crucial role in this process, and Dr Michalet quickly realised the importance of making this method accessible and easy to use. She therefore designed and produced the ‘Odorabox’ olfactory training kit, which contains local, organic essential oils, accompanied by simple instructions to be followed twice a day. In 2021, the Odorabox was integrated into a therapeutic education workshop called AGORA, aimed at helping Covid-19 patients regain their olfactory and gustatory abilities. This workshop has subsequently been adapted to meet the similar needs of patients undergoing chemotherapy, who experience comparable olfactory and gustatory problems.