WHAT ARE SMELL DISORDERS AND WHAT ARE THE TYPES?

People who have an inability to smell, decreased sense of smell, or changes in the way they perceive odors are considered to have a smell disorder. There are four main types of smell disorders:

• Hyposmia [high-POSE-mee-ah] is a reduced ability to detect odors.
• Anosmia [ah-NOSE-mee-ah] is the complete inability to detect odors. In rare cases, someone may be born without a sense of smell –a condition called congenital anosmia.
• Parosmia [pahr-OZE-mee-ah] is a change in the normal perception of odors, such as when the smell of something familiar is distorted, or when something that normally smells pleasant now smells foul.
• Phantosmia [fan-TOES-mee-ah] is the sensation of an odor that isn’t there.

WHAT CAUSES SMELL DISORDERS?

There are many causes of smell disorders, including aging, smoking, growths in nasal cavities, head injuries, chemical exposures, certain medications, radiation treatments, sinus and respiratory infections such as Covid-19, and nervous system conditions such as Parkinson’s and Alzheimer’s.  

HOW MANY PEOPLE EXPERIENCE SMELL DISORDERS?

Prior to the Covid-19 pandemic, it was estimated that smell disorders affected 22% of the population. Covid-19 has significantly and rapidly expanded this group. According to a November 2021 study published in JAMA Otolaryngology-Head & Neck Surgery, it is now estimated that between 700,000 and 1.6 million people in the United States have lost or have had a change in their sense of smell due to a Covid-19 infection. These individuals – who report smell disorders lasting more than six months – are part of a group known as Covid-19 “long-haulers.”

HOW DOES A SMELL DISORDER AFFECT ONE’S LIFE?

Smell disorders, while often misunderstood as harmless, can seriously impact an individual’s quality of life, emotional well-being, and safety. Your sense of smell can alert you to danger, like a gas leak, spoiled food, or a fire. Without a properly functioning sense of smell, you may miss important warning signs that are meant to keep you safe.  A smell disorder can also be an early sign of Parkinson’s, Alzheimer’s, or Multiple Schloeros (MS), so proper diagnoses and care are important.  

Your sense of smell also plays a huge part in your emotional well-being. According to a current study by the University of California San Diego, people with smell disorders would give up ten years of their life to live out their remaining years with a properly functioning sense of smell. Smell disorders can lead to depression and anxiety and in some cases, withdrawal from social activities.

In addition to the mental and emotional toll, smell disorders can also have severe impacts on eating habits, sometimes causing excessive weight loss or weight gain.  Some people experiencing Parosmia cannot eat at all and in extreme cases, drinking water becomes difficult. In other cases, people with smell disorders end up overeating as a result of not being able to detect and experience the satisfaction of flavor. For people with histories of disordered eating, smell disorders can be especially destructive. 

WHAT TO DO IF YOU ARE EXPERIENCING A SMELL DISORDER?

If you are experiencing a smell disorder, talk with your doctor. An Ear Nose and Throat (ENT) specialist will be most educated on Anosmia, Parosmia, Phantosmia, and Hyposmia. These doctors may want to perform a scope inside your nose to ensure that there are no growths or other causes impacting your smell and taste disorder.  Be prepared that you may need a referral from a primary care physician to see these ENT specialists, and your PCP may not be very familiar with smell disorders, because these issues were not as common prior to the Covid-19 pandemic. But, don’t lose faith, or avoid seeking medical care. In sharing your experience with medical professionals, you will be helping other patients by raising awareness about these important and increasingly common disorders.

ARE THERE ANY TREATMENTS OR CURES?  

Currently, there are no immediate cures for any existing smell disorders. However, there are treatments. Evidence suggests that olfactory training, also known as smell training, can increase the odds and speed of recovery from smell disorders. 

Think of smell training like physical therapy for your nose. Twice a day for twelve weeks, you’ll smell the same four scents and try to remember what they used to smell like, before your sense of smell became altered. This process attempts to retrain your brain to smell again through exposure and memory. Smell training can also help you identify smells that may not have changed with your smell disorder, which can be useful for finding foods and scents you can tolerate.

Some patients have also had success with saline nasal rinses. This low-risk treatment may help your sense of smell if it is affected by infection or allergy. Nasal rinsing cleans and flushes out debris and mucus from the nose and nasal sinuses. Some physicians may prescribe a steroid along with the nasal rinse.

Additional treatments are being explored via ongoing clinical trials. There is some evidence that Omega-3 supplements and Vitamin A drops may be helpful for smell disorders. At SMELP, we are dedicated to following the science. As more data becomes available, we will share it with our community and include additional treatment options in updated SMELP bundles.

RESOURCES

(N.d.). Nih.Gov. Retrieved December 14, 2021, from https://www.nidcd.nih.gov/sites/default/files/Documents/health/smelltaste/nidcd-smell-disorders.pdf