About Anosmia (Lost or Changed Sense of Smell)

Overview

Anosmia refers to the complete loss of the sense of smell. It can also be used to indicate a decreased sense of smell. This condition can result from various factors such as head injuries, problems with the nasal passages, or severe viral infections of the upper respiratory tract. In some cases, people are born without a sense of smell, which is known as congenital anosmia. Other types of smell dysfunction include hyposmia (partial loss of smell), parosmia (distorted perception of smells), and phantosmia (believing to smell something that isn't there). Anosmia can have a significant impact on a person's life. However, there is reason to be hopeful for future advancements in understanding and treating this condition.

Causes and Risk Factors

Anosmia can have various disease causes and risk factors. Here are the details:

Disease causes of anosmia:

Head trauma: A severe head injury can damage the olfactory nerves responsible for transmitting smell signals to the brain.
Nasal problems: Conditions such as chronic sinus or nasal diseases can affect the nasal passages and impair the sense of smell.
Viral infections: Severe upper respiratory tract infections, especially those caused by viruses, can lead to temporary or permanent anosmia.

Non-modifiable risk factors for anosmia cannot be changed or controlled. These include:

Aging: As people age, their sense of smell may naturally decline, making them more susceptible to anosmia.
Congenital anosmia: Some individuals are born without a sense of smell due to genetic factors.

Modifiable risk factors for anosmia can be influenced or changed. These include:

Chronic sinonasal diseases: These conditions can lead to anosmia, whether caused by blockages in the nasal passages (conductive) or issues with the nerves responsible for detecting smells (neurosensory). Managing these diseases effectively may help reduce the risk.
Environmental factors: Exposure to certain chemicals or toxins over time may increase the likelihood of developing anosmia. Reducing exposure to these substances can be beneficial.

It's important to note that these risk factors do not guarantee the development of anosmia, but they may increase the chances. If you have concerns about your sense of smell, consult with a healthcare professional for an accurate diagnosis and appropriate management.

Symptoms

The most common early symptoms of anosmia include:

Loss of the sense of smell
Reduced ability to smell (hyposmia)

As anosmia progresses or becomes more severe, other common symptoms that may occur include:

Alteration in taste
Loss of appetite
Depression

It is important to note that the persistence of anosmia can also be associated with symptoms such as ageusia (loss of taste). Remember to consult with your healthcare professional for a proper diagnosis and treatment.

Diagnosis

To diagnose anosmia, doctors may perform the following examinations, tests, and procedures:

Medical history and physical examination: Doctors will check the nasal passages, sinuses, and surrounding structures. They will also ask about the person's medical history and if they are experiencing any other symptoms.
- Self-reporting: Doctors rely on patients to self-report a loss of or change in their ability to smell. Improving health questionnaires may help doctors diagnose anosmia better.
- Diagnostic questionnaires: These questionnaires ask both younger people and older adults about changes in their sense of smell and whether have experienced phantom smells (sensing odors that aren’t there).
- Olfactory function index: This is a tool used to check how well a person can smell. The National Health and Nutrition Examination Survey (NHANES) self-reported olfactory function index offers a reliable method to screen for anosmia. It helps doctors identify more people with anosmia based on their self-reporting.
Scratch-and-sniff test: This test helps determine whether someone has anosmia or hyposmia (reduced sense of smell).
Nasal endoscopy: A nose and throat specialist may perform a nasal endoscopy to inspect the nasal and sinus cavities using a long, thin tube with a camera on it.
MRI (magnetic resonance imaging) scan: If other tests do not reveal a cause, an MRI scan may be recommended to assess the areas in the brain that detect smells.

It is important to contact a doctor if you recognize a loss of or change in your sense of smell. They can determine the appropriate examinations, tests, and procedures based on your specific situation.

Treatment Options

The goals of treatment for anosmia are to improve the sense of smell and enhance overall quality of life. Here are the recommended treatments and how they work to achieve these goals:

Smell training: This involves regularly exposing yourself to different scents and trying to identify them. It helps retrain your brain to recognize smells and can improve your sense of smell over time.
Medications: Depending on the cause of anosmia, different medications may be prescribed. For example, corticosteroids can reduce inflammation in the nasal passages. In COVID-19-related cases, certain medications, such as neuroprotective drugs (which protect nerve cells from damage) or depolarizing drugs (which help restore nerve signals), may help improve the sense of smell.
Therapeutic procedures: In some cases, surgical excision may be recommended to remove nasal masses causing anosmia.
Self-care and health behavior changes: Making lifestyle changes such as avoiding exposure to toxic agents and managing sinonasal diseases or upper respiratory viral infections can help prevent or improve anosmia.

It's important to note that treatment options may vary depending on the underlying cause of anosmia. Consult with your doctor for personalized advice and recommendations.

Medication dosing may be affected by many factors. Check with your health care professional about dosing for your individual situation. Side effects can occur. Check with your health care professional or read the information provided with your medication for side effect information