On the morning after Christmas 2020, Carolyn Hinds woke up and realized she couldn’t smell or taste anything. In the days that followed, COVID-19 symptoms like muscle pains, fever and cough were also present. Although these symptoms went away with time, her loss of sense and taste didn’t.
To this day, Hinds, 38, can barely smell anything, and her sense of taste remains warped—sweet things leave a strange aftertaste, salty foods upset her stomach and spice makes her lips and tongue burn but tastes like nothing. “These things will mess with you mentally and physically because it changes the way you experience the world,” she says.
Perhaps worst of all, Hinds’ doctors have said they don’t know how to treat her. “It’s been 10 months,” she says. “I’m kind of thinking this is how it will be [forever].”
Almost two years into the COVID-19 pandemic, lots of people are in Hinds’ position. Smell loss isn’t a COVID-specific phenomenon—it can happen due to other viruses, neurologic disorders, smoking, head injuries and normal aging, among other causes—but the pandemic has greatly increased its prevalence.
The SARS-CoV-2 virus seems to infect and compromise the cells neighboring those that control smell, which can translate to smell loss, explains Dr. Carl Philpott, a professor of rhinology and olfactology at the U.K.’s University of East Anglia. According to an international review, nearly half the COVID-19 victims lose their senses of smell and 40% lose their taste sense. Philpott suggests that some senses of taste and smell may be affected by taste loss. According to preliminary research, as many as half of those individuals also develop what’s known as parosmia, which distorts scents—subbing in, say, the smell of spoiled milk where there should be the aroma of coffee.
“Prior to COVID, we didn’t really have a lot of treatments or interventions that we can use for these patients,” says Paule Joseph, a clinical investigator at the National Institutes of Health who focuses on chemosensory disorders. “Now we find ourselves in the middle of this pandemic, with a group of people recovering with not a lot to offer.”
Although it might be minor inconveniences, the loss of smell can prove to be more serious than COVID-19-related complications. To ignore the importance of sharing a meal with family and friends is not to acknowledge the value of enjoying the pine-scented festivities of Christmas trees. “That inability to partake in the simple pleasure of life really starts to weigh on people and detracts from their overall quality of life and even leads to depression and anxiety and social withdrawal,” says Dr. Zara Patel, a head and neck surgeon and smell-loss expert at Stanford University.
Patel says that smell is linked to many subconscious processes such as choosing romantic partners or bonding with parents-children. And there are safety concerns associated with sense loss, like not noticing that food has gone bad or failing to smell smoke when there’s a fire.
For all these reasons, treating smell loss is important—but that’s easier said than done. Anyone can walk into an eye doctor’s office, take a vision test and know if they need glasses. “We don’t have that for the sense of smell, the sense of taste,” Joseph says. “We don’t have clinical guidelines,” which makes it difficult to offer effective treatments.
However, there have been some attempts to monitor the rate of recovery in smell among COVID-19-infected patients. The October One study found that COVID-19 affects 80% of patients who experience loss of sense of taste or smell. Adults younger than 40 are more likely to recover their function. But as with so many symptoms of what’s now known as Long COVID, there is a significant subset of people for whom these issues drag on and on.
The field’s standard therapy is what’s known, logically enough, as “smell training.” It involves sniffing strong-smelling substances—typically cloves, rose, lemon and eucalyptus—each day in hopes of re-forging the pathways that mediate scent. However, smell training may take up to a few months and many people find it not effective.
Patel’s trial, in which he consulted for many pharmaceutical and medical companies, showed that scent training works better when patients rinse their nasal cavities with a solution that contains a corticosteroid to reduce inflammation. However, not all experts believe these medications are the best. Philpott reviewed all previous research regarding corticosteroids, and found no evidence that they reduce smell loss in COVID-19 patients.
Philpott next will investigate whether nasal drops containing Vitamin A may be an effective treatment. Based on promising German research, Philpott has already begun to look into this possibility. Patel, for her part is investigating whether platelet-rich plasma injections could restore the sense of smell. Participants are currently being enrolled in her study. Patel’s research also suggests omega-3 supplements can be effective for some people, but she cautions that she hasn’t studied them specifically among people who lost their sense of smell from COVID-19.
Many have turned to home remedies to solve the problem of no failsafe solutions. TikTok posted a video this winter that claimed eating burned orange rind with brown sugar could help. While that trick is probably harmless, if not evidence-based, Patel says she’s heard of far more damaging plans, like using nasal sprays laced with zinc—a mineral that can actually destroy the sense of smell.
The best thing patients can do is see a doctor—preferably one with experience in smell and taste disorders, if possible—shortly after experiencing smell loss, Patel says. “It is just much, much harder to bring someone’s smell back [with] the more time that passes,” she says.
Joseph reiterates the importance of progress. Patients came together to form advocacy groups such as the Smell and Taste Association of North America. These groups can provide support and drive for further research. With COVID-19, researchers have been able to study smell loss in greater numbers than ever. Already, they’ve had some success. Researchers have created a simple test for smell that involves a single card and three attached patches. Only one patch is actually scent. Based on an individual’s ability to pick out which one that is, and their assessments of its strength and characteristics, doctors can start to gauge the severity of their smell loss.
That’s a promising start, Joseph says, but it’s only one step on the road to effective treatments. “We can develop measurements … but we can’t measure for measurement’s sake,” she says. “We have to be able to offer something to patients.”