“Phantom odor”—an unexplained and nonexistent smell, such as burning hair—is a fact of life for 1 in 15 American adults aged > 40 years, according to a study at the National Institute on Deafness and Other Communication Disorders. And it can complicate daily life: The sense of smell has an impact on appetite, food preferences, and the ability to detect dangerous smells, such as gas leaks and spoiled food. People with the disorder may even have trouble maintaining a healthy weight.
The researchers analyzed data from 7,417 participants in the 2011-2014 National Health and Nutrition Examination Survey. The survey included the question “Do you sometimes smell an unpleasant, bad, or burning odor when nothing is there?”
Adults aged 40 to 60 years had the highest prevalence of phantom odor perception. Women were twice as likely as men to report phantom odors—female predominance was “particularly striking” for those aged < 60 years, the researchers say. Interestingly, phantom odor perception is not related to the individual’s ability to correctly identify odors.
What causes the problem is poorly understood. It might be related to overactive odor-sensing cells in the nasal cavity or perhaps a malfunction in the part of the brain that understands odor signals, said Kathleen Bainbridge, PhD, study leader.
Risk factors for smelling phantom odors include head injury, dry mouth, and poor health. Low socioeconomic status also is a factor: Poor people may be exposed to more environmental pollutants and toxins. Other possibilities include effects of medicines.
To find out the cause—and ultimately develop treatments—a “good first step,” says Bainbridge, “is a clear description of the phenomenon.”