Taste and Smell Disorders Are Devastating and Surprisingly Common

Stories from New Scientist.
May 12 2013 8:15 AM

The Unappreciated Senses

The world is a bleak place if you lose your sense of taste or smell.

Imagine a world without the pleasures of smell.
Imagine a world without the pleases of smell.

Photo by Regis Duvignau/Reuters

Taste and smell disorders can be devastating, but often such problems get no treatment. Carl Philpott, director of the United Kingdom's only clinic devoted to taste and smell disorders, explains how these conditions can completely change your experience of the world.

Mick O’Hare: How many people are affected by taste and smell disorders?
Carl Philpott: It's tough to put a precise figure on it, but the best estimate is around one in 20. In the United Kingdom alone, this adds up to more than 3 million people. As a comparison, one in 30 people in the United Kingdom have some form of sight loss, and one in six have a hearing disorder.

MO: Why are these senses so important?
CP: They are a huge part of everyday life. Eating is essential for our survival, and enjoyment of food and drink ensures this process is maintained. These senses also serve as a hazard warning system to help us avoid dangers such as gas leaks and spoiled food. Smell ensures we maintain our personal hygiene and offers us an essential interaction with the world around us—giving pleasure from simple things such as flowers. For many people smell also helps to re-create memories.

MO: Given how disruptive it can be to lose your sense of taste or smell, why aren't more people clamoring for treatment?
CP: Many are unaware that they can be treated, and others underestimate their smell loss. For example, chronic sinusitis, which is treatable, will affect 11 percent of people at some point in their lives. Since our clinic opened, we have been overwhelmed by referrals and requests for treatment. We have unleashed a torrent of people who have been waiting for an outlet; many have been suffering in silence for years.

MO: What are the consequences for people with olfactory disorders?
CP: The tongue only detects the basic tastes of salt, sweet, bitter, sour, and umami—which is a savory, hearty taste. It's the nose that provides you with the flavor of food. Loss of smell, and with it any experience of food flavor, is quite devastating. Coming to terms with the loss of an entire sense or even two often leads to other difficulties—including depression and thoughts of suicide.

MO: With the severe impact these conditions can have, why aren't there more dedicated clinics like yours?
CP: There is a sense of apathy due to the relative lack of understanding of these senses. The impact of their loss is underrated, and there is a perception that nothing can be done.

In addition, a lack of interest in clinical practice means the teaching of this subject in medical schools is poor. Most medical schools allocate only a small percentage of time in their courses to the ear, nose and throat discipline.

MO: And yet there are many establishments dedicated to loss of sight and hearing. Why is that?
CP: The ear dominates the ear, nose, and throat discipline, and although specialists should be open to treating olfaction and gustation disorders, the nose is often considered a poor and uninteresting relative. Anosmia, or the loss of the sense of smell, is not often regarded as a major treatment priority.

MO: Is that because taste and smell are viewed as less essential senses?
CP: Yes, they are often seen that way. People with such disorders look "normal" and can function with less obvious disability than people without sight or hearing. As a result they are most often advised to go away and try to live with the condition, leaving many struggling to cope. It is often as important to treat the associated depression, which can affect more than half of people with taste and smell disorders, as it is to combat the olfactory or gustatory loss.

MO: What causes most taste and smell disorders?
CP: There are four most common causes, including chronic rhinosinusitis, or persistent inflammation of the sinuses and nasal passages, which blocks up the nose and creates pressure and facial pain. Then there is head injury, when the brain may get bruised and the olfactory nerves injured, and the common cold virus, which can damage the cells of the olfactory epithelium, the specialized tissue that lines the inside of the nasal cavity. Finally, some cases are idiopathic, meaning they have no obvious cause.

MO: How many of these can be treated—or cured?
CP: None can be cured as such, but chronic rhinosinusitis is very treatable: More than 90 percent of patients in this category can regain their sense of smell after steroid treatment to reduce inflammation. In the other cases, there are medications we can use. Oral corticosteroids are always tried first, to make sure the underlying condition is not caused by inflammation from allergies, for example.

Distortions of smell, or parosmias, can sometimes be treated with small doses of anti-epileptics. That's because these distortions can be caused by the brain misinterpreting signals it receives—leading people to experience a range of things, from everyday foods tasting strange to detecting foul smells all the time. These can be very distressing and cause severe eating disorders, ruining individuals' lives.

MO: Given the lack of attention to olfactory illness, have there been many recent medical advances in treatment?
CP: There is a lot of ongoing research, but unfortunately not much is translating into new treatments. Essentially that is why the clinic exists—to explore these. At the moment, I am completing a study to evaluate a spray containing sodium citrate that may temporarily reverse poor sense of smell. I am also applying for funding for further drug trials. As always, though, it's a slow process.

MO: What coping strategies do you propose for those who will never regain the sense of smell or taste?
CP: We advise people about issues of domestic safety, using a gas detector, for example; and personal hygiene, to be sure you wash a lot. And we talk to people about smell training, to heighten what little olfaction they may still possess.

MO: How can people improve their sense of smell through training?
CP: It is about making the most of what you have. We provide suggestions for enhancing food—altering spiciness or texture, for example—to make it more enjoyable. If you can still slightly taste spices, make your food hotter using chilies. Or alter the texture: Make it more creamy or crunchy.

MO: What are the hardest parts of life without the sense of taste or smell?
CP: Anosmia sufferers really miss the enjoyment of food. Some find mealtimes to be the most dreadful moments of their lives. They know they have to eat to live, but all the pleasure has gone. Many will avoid restaurants and will find social situations that involve food and drink very difficult to deal with. They feel disconnected from their environment in a way that non-anosmics do not appreciate. It's like being invited to a concert when you can't hear the music.

This article originally appeared in New Scientist.