Q
: Why is anosmia , or the loss of smell , an important red flag when it comes to COVID-19 ?
A
: The COVID-19 virus is the “ Master of Stealth ” because many of its symptoms are indistinguishable from the common flu or food poisoning . It has a long incubation period during which it lurks in the unsuspecting and can spread via asymptomatic and healthy-looking individuals .
One symptom , however , stands out — acute onset anosmia . Uncommon in the usual flu or cold , its appearance must raise the suspicion of a COVID-19 infection until proven otherwise .
Q
: What are the signs of anosmia ?
A
: Someone with anosmia will complain of a near total lack of or change in the sense of smell . One may not smell one ’ s cooking or even cigarette smoke or durian . Hyposmia occurs when the sense of smell is reduced . Often , anosmia is accompanied by dysgeusia , a lost or altered sense of taste .
Q
: How to distinguish an ear , nose and throat ( ENT ) cause from COVID-19 ?
A
: Common causes of anosmia and hyposmia could be a nose block caused by inflammation or infection of the nasal passages that interrupts the airflow in the nose , preventing smell molecules from reaching the smell receptors sited right at the top of the nose , at the base of skull . Viruses can damage the nerves related to smell .
In the context of a COVID-19 acute anosmia , the result would be a lost or altered sense of smell for less than two weeks , without any head injury or known chronic sinusitis . Interestingly , the anosmia of COVID-19 is often not associated with any blockage of the nose , unlike in the usual flu and colds . Anosmia can be the only symptom in COVID-19 patients who otherwise can feel perfectly well but also can transmit the virus to others .
COVID-19 infections manifest as symptoms of inflammation in the ear , nose , and throat commonly . To distinguish if anosmia is due to the usual flu or cold due to non-COVID-19 type viruses and bacteria is not easy . Reports of anosmia in COVID-19 cases have ranged from five percent to over 80 percent worldwide , depending on whether those studies looked for anosmia as a symptom specifically . Anosmia can also precede other symptoms of COVID-19 .
New-onset acute anosmia has been shown to be the best predictor of COVID-19 . COVID-19 patients have been noted to be even 27 times more likely to have anosmia , but only about 2.5 times more likely to have fever , nose block , runny nose , and cough compared to non-COVID-19 patients . Any acute anosmia must thus be managed as a suspected COVID-19 case until a PCR swab test has proven otherwise .
Q
: How often is anosmia a serious problem ?
A
: European multicenter studies have reported that anosmia persisted after the other COVID-19 symptoms resolved in over 50 percent of patients . For those who recovered their sense of smell , over 95 percent recovered within two weeks of resolution of the other symptoms .
A recent Harvard study indicated that COVID-19 affects the supporting cells and not actual neuron cells of the smell receptors . The implication is that COVID-19 is unlikely to cause permanent loss of smell . Reports from those who have recovered from COVID-19 suggest this is the case .
Q
: Since anosmia is one of the symptoms associated with COVID-19 , should patients consult a GP or an ENT specialist ?
A
: Patients should consult a clinic able to manage COVID-19 patients , be it a GP , ENT clinic , polyclinic , or hospital . Calling ahead is a must to check on this , as capabilities will differ from place to place . The clinic should have the set-up , training , manpower , and resources to safely isolate a suspected COVID-19 case .
Q
: What are the treatment options available and their efficacy ?
A
: Most cases of anosmia can recover over time and be treated by general practitioners . If the anosmia is due to an infection and inflammation , nasal decongestants , antihistamine , steroid nose sprays , and antibiotics can help . Giving up smoking is also helpful . If it ’ s not due to an infection and is chronic for more than six weeks , it ’ s advisable to seek an ENT evaluation to exclude nasal polyposis or the rare smell organ tumour .
Dr Lynne Lim Hsueh Yee
Dr Lynne Lim Hsueh Yee is an ENT specialist in Singapore .
GlobalHealthAsiaPacific . com NOVEMBER 2020
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