Earlier this month, the Centers for Disease Control and Prevention added six new coronavirus symptoms to its list, including new loss of smell or taste. These additions confirmed widespread speculation that anosmia, or loss of smell, was among the symptoms of COVID-19, which include cough, shortness of breath, fever, chills, muscle pain, headache, sore throat and repeated shaking with chills.
The addition of impaired taste and smell to the list of coronavirus symptoms has prompted questions about the merit of other symptoms and specifically if an uncomfortable, metallic taste is a reliable indicator of the coronavirus.
Here’s what you need to know:
Anecdotal Evidence Suggests That Distorted Taste May Be A Symptom of Coronavirus
Places like Express and Inc. have reported anecdotal instances in which those who had the virus experienced an uncomfortable metallic taste in their mouths. On March 22, the American Academy of Otolaryngology reported, “[a]necdotal evidence is rapidly accumulating from sites around the world that anosmia and dysgeusia are significant symptoms associated with the COVID-19 pandemic.”
Dysgeusia, or distorted taste, “is a condition in which a foul, salty, rancid, or metallic taste sensation persists in the mouth,” according to the National Institute of Health. Symptoms of disordered taste are very often attributed to smell disorder because the two senses are so closely linked. True loss of taste is rare. NIH reports that “[t]he most common taste disorder is phantom taste perception: a lingering, often unpleasant taste even though there is nothing in your mouth.”
“The sense of taste and smell are very closely related,” said Dr. D.J. Verret in an interview with ABC. “We know from previous research that coronavirus infections are seen in post-viral anosmia. It is therefore not a stretch to think that COVID-19, caused by a coronavirus, can result in smell or taste disturbances.”
The Effort To Identify COVID-19 Symptoms Is Ongoing
In March, the Academy requested that anosmia and dysgeusia be added to the list of symptoms, noting that, “[a]nosmia, in particular, has been seen in patients ultimately testing positive for the coronavirus with no other symptoms.”
For those experiencing a distorted sense of taste or smell, the Academy recommends they, “alert physicians to the possibility of COVID-19 infection and warrant serious consideration for self-isolation and testing of these individuals.” Exceptions apply to those with respiratory diseases like allergic rhinitis, acute rhinosinusitis, or chronic rhinosinusitis.
The CDC suggests that those experiencing loss of taste or smell, but not a cough or shortness of breath, should experience a secondary symptom like headache or fever before assuming they have COVID-19. CDC guidelines do not include recommendations for those experiencing distorted taste but do note that “[t]his list is not all inclusive. Please consult your medical provider for any other symptoms that are severe or concerning to you.”
Loss of Smell Is Relatively Common In Those With Viral Infections
According to Verret in his interview with ABC, 40% of patients recovering from a viral illness report a loss of their sense of smell. This suggests that those infected with the coronavirus may experience disordered smell, which is linked to disordered taste. On the other hand, those same symptoms might indicate other viral infections like the common cold.
“There is a risk that the media attention is leading patients with post-viral anosmia caused by unrelated viral infections, known to peak in February and March, to wrongly attribute their anosmia to the COVID-19 pandemic,” says ENT U.K., a professional organization dedicated to ear, nose and throat surgery which brought international attention to the prevalence of anosmia in coronavirus patients. ENT U.K. stands by its assessment that anosmia, in the absence of head trauma and blocked nasal passages, is a symptom of COVID-19 but has not confirmed that dysgeusia is also a symptom.
Taste and olfactory disorders can be attributed to several causes, including head trauma, ear infection, exposure to insecticides, stroke, dementia, and poor hygiene and dental health. NIH reports that more than 200,000 people visit a doctor for taste- and smell-related problems each year. Seasonal allergies can also contribute to impaired smell and taste.