Scientists are recommending “smell training” for people who have lost the sense due to Covid, as one in five with the symptom report it has not returned to normal eight weeks after becoming ill.
The exercise involves sniffing at least four different odours twice daily for several months, which experts say is a “cheap, simple and side-effect free” way of treating the common symptom that affects some people for several weeks after contracting the virus.
Prof Carl Philpott, a smell loss expert at the University of East Anglia’s Norwich Medical School, said the method aimed to help patients’ recovery based on neuroplasticity, which he defined as “the brain’s ability to reorganise itself to compensate for a change or injury”.
Anosmia, the medical term for temporary or permanent smell loss, is one of the key signs of the disease. One study by Pennsylvania State University last October found that between 44% and 77% of Covid patients experienced complete loss of smell during the acute stage of their illness.
In the research paper recommending the nasal exercise, published in the journal International Forum of Allergy & Rhinology, the global team of experts also warned against using steroids to treat anosmia.
Philpott said there was “very little evidence” anti-inflammatory drugs were a useful treatment and carried “potential side-effects including fluid retention, high blood pressure, and problems with mood swings and behaviour”.
Although anosmia due to Covid has affected “huge” numbers globally, Philpott added that most people “regain their sense of smell spontaneously”, citing research that shows that 90% fully regain the ability after six months.
The delay in adding smell loss to the UK’s official list of symptoms during the early stages of the pandemic is believed to have led to tens of thousands of cases being missed.