The Grapevine

What Is Phantom Odor Perception?

Most of us have heard of visual hallucinations i.e. seeing things that are not actually there. It is relatively lesser known that some people can experience something similar related to their sense of smell.

Smelling something foul (like an ashtray or burning hair) despite no source could mean that a person is affected by something known as phantom odor perception. New findings suggest that nearly 6.5 percent of Americans over the age of 40 have experienced it.

The study was published in JAMA Otolaryngology-Head and Neck Surgery on Aug. 16.

"Problems with the sense of smell are often overlooked, despite their importance," said Dr. Judith A. Cooper, acting director of the National Institute on Deafness and Other Communication Disorders (NIDCD).

"They can have a big impact on appetite, food preferences, and the ability to smell danger signals such as fire, gas leaks, and spoiled food."

According to the authors, this is the first study in the United States to use nationally representative data to estimate the prevalence of phantom odor perception and highlight the risk factors.

Sourced from the 2011-2014 National Health and Nutrition Examination Survey, the data included over 7,400 participants who were over 40 years of age.

It was estimated that 1 in 15 Americans (or 6.5 percent) in this age group experienced phantom odor perception. The participants were asked if they ever happen to smell something unpleasant when nothing is there — their answers were analyzed for potential correlations with participant characteristics. 

The prevalence of the condition was high in the 40 to 60 age group. The team also noticed a gender difference since twice as many women reported phantom odors when compared to men. 

When experiencing symptoms, seeing a doctor is recommended to identify the underlying cause. While the condition may only be temporary, it could potentially be a sign of something serious. Head injuries, respiratory infections, dry mouth, and poor overall health are risk factors.

Lower socio-economic status was also thought to be a potential risk factor. It was hypothesized that people in this group are more exposed to harmful pollutants and toxins contributing to phantom odor perception either due to other health conditions or the medications taken to treat them.

"The causes of phantom odor perception are not understood. The condition could 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 the study's lead researcher Kathleen Bainbridge who is from the NIDCD.

"A good first step in understanding any medical condition is a clear description of the phenomenon. From there, other researchers may form ideas about where to look further for possible causes and ultimately for ways to prevent or treat the condition."