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Smell (olfactory) disorders can present in many forms: complete loss (anosmia), reduced loss (hyposmia), or change in smell (parosmia or phantosmia). All forms can be quite debilitating and affect 6 million people in the U.S.

Not being able to detect bad smells can be quite troublesome, such as a parent not being able to detect the smell of a dirty diaper, or even dangerous, such as not smelling smoke or natural gas fumes.

The Relationship Between Loss of Smell and Loss of Taste

You’d be surprised how your sense of smell is directly connected to your sense of taste. 80% of taste disorders (ageusia) are from an impaired sense of smell.

When you eat, special chemical substances called aromatics are released and travel from the back of your throat up to your nose. These aromatics stimulate your nose and, coupled with your taste buds, determine how you perceive food.

Causes of Loss of Smell and Taste

Olfactory disorders have many causes, and a specialist such as an ear, nose, and throat (ENT) doctor is typically necessary to sort out the root cause. As a rule, if you have lost your sense of smell for more than two weeks, you should seek a physician to determine the cause.

Nasal Obstruction

The most common cause for loss of smell and taste is simply nasal obstruction, such as from congestion due to a cold or bad allergies. Long-standing nasal obstruction from something like nasal polyps or severe nasal septal deflections can also be a cause of obstruction.

Either way, if your nose is blocked, you won’t be able to get those aromatic particles to reach the top of your nose to stimulate the nerves of olfaction.


The second most common cause is damage from an infection, especially viruses. Viruses are known to damage all kinds of nerves (especially cranial nerves), including the nerves in the nose used for smell.

After a viral infection, sense of smell typically returns within two weeks, although recovery can vary from weeks to months. Permanent damage to the nerves may also occur.


The coronavirus that has led to the COVID-19 pandemic has caused an increase in patients losing their sense of smell and taste. Like any virus, the coronavirus attaches to the nasal receptors (specifically the ACE2 receptor) and causes damage.

In our clinic, we’ve found that recovery is often extended to several months post-COVID and is often associated with a temporary phase of parosmia, where your sense of smell or taste changes (oftentimes for the worse).

Additional Causes

Less common causes of olfactory disorders include head trauma (concussions), various nasal and brain masses and tumors, neurodegenerative disorders (dementia), as well as toxin and medicine side effects. In some patients, the cause may simply be unknown.

[Related: What Can Cause Loss of Smell?]

Treatments for Loss of Smell & Taste

In Dr. Pasha’s clinic, several steps are required in the work-up of olfactory issues to formulate a treatment plan, including nasal endoscopy (a painless microscopic evaluation of the nose), allergy testing, and a CT scan (X-ray). All tests can be performed in the office.

Treatment for loss of smell and taste depends on the cause. For example, if you have nasal polyps, then have them removed. If you have a viral infection, you may need to take medications to reduce the inflammation caused by the infection.

For those who have long-standing loss of smell, olfactory training (or smell training) may be beneficial. Dr. Pasha has his own olfactory training regimen that he may provide for you. The future of anosmia management is growing and includes stem cell research and even gene therapy for some congenital causes.

Loss of smell can be frustrating for patients. The key is to spend the time necessary to identify the cause so you can focus your therapy.

Loss of Smell & Taste FAQs

What Is Olfactory Training?

Olfactory training is a method to restimulate the nose to recognize smell.

A simple method is to gather four different major scents. Most common are lemon, rose, cloves, and eucalyptus, usually from essential oils. Place these scents under your nose twice a day. The goal is to try to reconnect the connection of smell with the brain. The method may take months, but there are no risks or high costs.

Dr. Pasha and his staff have their own olfactory training program that may be prescribed for you.

Do Corticosteroids Work?

Corticosteroids in the form of a nasal spray or medication by mouth have variable success rates. Depending on the potential cause of your loss of smell and taste, Dr. Pasha may prescribe a course to reduce the inflammatory damage that affects olfactory nerves.

What About Surgery for Loss of Smell?

That depends. If the cause of your loss of smell is from the obstruction caused by nasal polyps or structural blockage, Dr. Pasha may suggest a procedure to open up your nasal passages.

What Can Cause Loss of Smell?

Having trouble smelling things around you is not normal and could be caused by several conditions. The complete or partial loss of smell is called anosmia and it can be temporary or permanent, depending on what caused it. Loss of smell is usually a symptom of another medical condition.

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How Olfactory Training Can Help You Regain Your Sense Of Smell

Has recovering from a viral infection left you without a sense of smell? Or maybe you’ve notices a change in how you smell and now aromas you used to love are making you grimace.

Read More