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We understand that anosmia can significantly impact your quality of life. Our team determines the cause of smell disorders so we can provide effective treatments. ## Overview What is anosmia? The process of smelling involves your nose and your brain. The inside of your nose contains special cells called olfactory neurons. These neurons, or odor receptors, send your brain messages about scents they detect. When your brain receives one of these messages, it recognizes and identifies the smell. A problem or blockage anywhere in this process can affect your ability to smell. Usually, anosmia and hyposmia improve once doctors have treated the cause. In some cases, loss of smell can be permanent. If you notice symptoms of anosmia, it is important to seek treatment right away. Delaying treatment may result in permanent smell loss. Treatments may include changing medications, treating an infection (such as COVID-19), smell retraining therapy, or surgery to remove a blockage. Our world-renowned team has unparalleled expertise in smell disorders. Your care team will work with you to determine the most appropriate treatment plan. ## Connect to Care Let us help find personalized care options for you and your family. [Make an Appointment](https://stanfordhealthcare.org/medical-conditions/ear-nose-and-throat/anosmia-loss-of-smell.html) [Find a Doctor or Provider](https://stanfordhealthcare.org/directory/directory.html/&sp_conditions%7C/medical-conditions/ear-nose-and-throat/anosmia-loss-of-smell.html%5EAnosmia%20\(Loss%20of%20Smell\)#x1=sp_spec_care_phy&q1=true) [Find a Clinic](https://stanfordhealthcare.org/directory/directory.html/&sp_conditions%7C/medical-conditions/ear-nose-and-throat/anosmia-loss-of-smell.html%5EAnosmia%20\(Loss%20of%20Smell\)#x1=sp_spec_care_clinic&q1=true) [Online Second Opinion](https://stanfordhealthcare.org/second-opinion/overview.html) ## Understanding Anosmia and Hyposmia Symptoms **Anosmia and Hyposmia Symptoms** Signs of anosmia and hyposmia can come on suddenly or develop gradually. You may experience a change in your sense of smell before losing it completely. Familiar scents may smell different (parosmia), or you may detect odors that aren’t actually there (phantosmia). For some people, one of the first symptoms of anosmia and hyposmia is loss of taste (ageusia). You may notice that your food tastes more bland than usual. Or you can’t tell the difference between certain flavors and discover that your ability to smell has decreased. This happens because the sense of smell and sense of taste are very closely connected. To taste flavors, your brain combines the messages it receives about smell and taste. Causes **Causes of Anosmia and Hyposmia** Anosmia and hyposmia can affect people of any age or gender, but smell disorders are more common in men. These conditions can result from: - **Age**: After age 60, many people experience hyposmia, a reduced sense of smell. It’s rare to experience a complete loss of smell with age. - **Allergies and illnesses**: Nasal congestion and inflammation from allergies, influenza (flu), and the common cold can make it difficult or impossible to smell. - **COVID-19 and other viral infections**: Anosmia is a common symptom of COVID-19 and long COVID. Many other viral infections can also cause this condition. Usually, the sense of smell returns in a few weeks, but it can take months or even longer to return. - **Degenerative disorders**: [Alzheimer’s disease](https://stanfordhealthcare.org/medical-conditions/brain-and-nerves/alzheimers-disease.html), [Parkinson’s disease](https://stanfordhealthcare.org/medical-conditions/brain-and-nerves/parkinsons-disease.html), Lewy body dementia, and [multiple sclerosis](https://stanfordhealthcare.org/medical-conditions/brain-and-nerves/multiple-sclerosis.html) (MS) can damage odor receptors and cause smelling abnormalities. Hyposmia and anosmia are often early signs of these disorders. - **Genetics**: Rarely, people are born without the ability to smell. Doctors call this condition congenital anosmia. It results from certain genetic disorders, such as Kallmann syndrome, which also affects hormone development. - **Injury**: A [deviated septum](https://stanfordhealthcare.org/medical-conditions/ear-nose-and-throat/deviated-septum.html) (damage to the partition between the nasal cavities) can affect a person’s ability to smell. A traumatic brain injury can damage nerves in the brain responsible for communicating with olfactory nerves in the nose. - **Medications and chemicals**: Some drugs can cause anosmia, including antihistamines and nasal decongestants. The risk increases with long-term use of these medications. Exposure to toxic chemicals, such as insecticides, can also affect smell. - **Nasal polyps (noncancerous growths) and tumors**: Growths in the nose and sinuses can change how nerves work, resulting in anosmia. [Brain tumors](https://stanfordhealthcare.org/medical-conditions/brain-and-nerves/brain-tumor.html) can damage the area responsible for identifying smells. - **Radiation therapy**: People who receive radiation therapy for head and neck cancer may experience anosmia following treatment. - **Smoking**: Cigarettes and other tobacco products can affect the sense of smell, especially in people who have smoked for many years. Diagnosis **Anosmia and Hyposmia Diagnosis** Your doctor will review your medical history and ask about medications you’re taking. They will ask about your symptoms, including when they began, whether your taste is affected, and what type of symptoms you’re having, such as nasal congestion from allergies or an upper respiratory infection. Your doctor will examine you and look in your nose and throat. They may also recommend tests to confirm an anosmia diagnosis or rule out other conditions. These tests may include: - **CT scan, MRI, or other imaging studies**: These tests create detailed images of structures inside your head so that your doctor can spot any abnormalities or growths. They also help your doctor detect signs of degenerative disorders, such as Alzheimer’s disease. - **Nasal endoscopy**: For this test, your doctor inserts a thin, flexible tube with a camera down your nose. The camera shows your nasal and sinus passages. - **Olfactory nerve testing (smell testing)**: During this test, your doctor closes one nostril at a time and asks you to smell certain items, such as spices or coffee grounds. Your doctor may ask you to close your eyes, smell certain substances, and identify them based on how they smell. ## Connect to Care [Make an Appointment](https://stanfordhealthcare.org/medical-conditions/ear-nose-and-throat/anosmia-loss-of-smell.html) ## Why Choose Stanford? [Care at Stanford](https://stanfordhealthcare.org/medical-conditions/ear-nose-and-throat/anosmia-loss-of-smell/why-choose-stanford.html) ## View Treatment Options [Treatments](https://stanfordhealthcare.org/medical-conditions/ear-nose-and-throat/anosmia-loss-of-smell/treatments.html) Make An Appointment To request an appointment with a rhinologist, call **[650-723-5281](tel://650-723-5281)**. Anosmia (Loss of Smell) Anosmia (loss of smell) and hyposmia (partial loss of smell) can result from many conditions, including COVID-19. We offer advanced treatments and support. Anosmia Loss of smell loss of taste hyposmia ageusia symptom of covid nasal polyp nasal polyp symptoms deviated septum parosmia phantosmia Parkinson’s disease Alzheimer’s long covid Lewy body dementia [Treatments](https://stanfordhealthcare.org/medical-conditions/ear-nose-and-throat/anosmia-loss-of-smell/treatments.html) - [Find a Doctor or Provider](https://stanfordhealthcare.org/directory/guided-search.html#x1=sp_spec_care_phy&q1=true&page=1) - [Find Conditions & Treatments](https://stanfordhealthcare.org/directory/guided-search.html#x1=sp_type&q1=%2520&page=1) - [Find a Stanford clinic](https://stanfordhealthcare.org/directory/guided-search.html#x1=sp_spec_care_clinic&q1=true&page=1) - [For Patients & Visitors](https://stanfordhealthcare.org/for-patients-visitors.html) - [Billing](https://stanfordhealthcare.org/for-patients-visitors/billing.html) - [Help Paying Your Bill](https://stanfordhealthcare.org/for-patients-visitors/financial-assistance.html) - [Protections Against Surprise Medical Bills](https://stanfordhealthcare.org/for-patients-visitors/no-surprises-act.html) - [Price Transparency](https://stanfordhealthcare.org/for-patients-visitors/price-transparency.html) - [Insurance](https://stanfordhealthcare.org/for-patients-visitors/health-insurance-plans.html) - [Hospital Check-in](https://stanfordhealthcare.org/for-patients-visitors/hospital-check-in.html) - [Contact Us](https://stanfordhealthcare.org/about-us/contact.html) - [Video Visits](https://stanfordhealthcare.org/for-patients-visitors/video-visits/scheduling-a-video-visit.html) - [Send a Greeting Card](https://stanfordhealthcare.org/Ecard/ecard-intro-page.html) - [Get a Second Opinion](https://stanfordhealthcare.org/second-opinion/overview.html) - [COVID-19 Resource Center](https://stanfordhealthcare.org/discover/covid-19-resource-center.html) - [Behavioral Standards](https://stanfordhealthcare.org/for-patients-visitors/behavioral-standards.html) - [Patient Privacy Policy](https://stanfordhealthcare.org/for-patients-visitors/guest-services/patient-privacy.html) - [Make a Gift](http://medicalgiving.stanford.edu/) - [About Us](https://stanfordhealthcare.org/about-us.html) - [Quality & Safety](https://stanfordhealthcarequality.com/) - [Annual Report](https://stanfordhealthcare.org/about-us/annual-report.html) - [300 Pasteur Drive Renewal Program](https://stanfordhealthcare.org/about-us/300-pasteur-renewal-program.html) - [Sustainability](https://stanfordhealthcare.org/sustainability-program-office/sustainability-program-office.html) - [Stanford Health Care – Now](https://stanfordhealthcare.org/stanford-health-care-now.html) - [For Healthcare Professionals](https://stanfordhealthcare.org/health-care-professionals.html) - [Referring Physicians](https://stanfordhealthcare.org/health-care-professionals/physician-referral-center.html) - [Nursing](https://stanfordhealthcare.org/health-care-professionals/nursing.html) - [Allied Healthcare Professionals](https://stanfordhealthcare.org/health-care-professionals/allied-healthcare.html) [First Responders](https://stanfordhealthcare.org/content/shc/en-tools/modals/first-responders.html) - [Newsroom](https://stanfordhealthcare.org/newsroom.html) - [Careers](https://careers.stanfordhealthcare.org/) - [Volunteering](https://stanfordhealthcare.org/for-patients-visitors/volunteering.html) - [Vendors](https://stanfordhealthcare.org/for-vendors/vendors.html) - [Stanford Medicine Partners](https://stanfordmedicinepartners.org/) - [Stanford Health Care Tri-Valley](https://stanfordhealthcare.org/tri-valley) - [Stanford Medicine](http://med.stanford.edu/) - [Stanford Medicine Children's Health](http://www.stanfordchildrens.org/) - [Stanford University](http://www.stanford.edu/) [](https://stanfordhealthcare.org/) [Website Terms of Use](https://stanfordhealthcare.org/about-us/legal-disclaimer.html) [Website Privacy Policy](https://stanfordhealthcare.org/about-us/website-privacy-policy.html) [Code of Conduct](https://stanfordhealthcare.org/about-us/conduct.html) [Notice of Nondiscrimination](https://stanfordhealthcare.org/about-us/notice-of-nondiscrimination.html) © 2026 Stanford Health Care. 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Anosmia (Loss of Smell) Anosmia (total loss of smell) and hyposmia (partial loss of smell) can result from many conditions, medications, and infections. We understand that anosmia can significantly impact your quality of life. Our team determines the cause of smell disorders so we can provide effective treatments. What is anosmia? The process of smelling involves your nose and your brain. The inside of your nose contains special cells called olfactory neurons. These neurons, or odor receptors, send your brain messages about scents they detect. When your brain receives one of these messages, it recognizes and identifies the smell. A problem or blockage anywhere in this process can affect your ability to smell. Usually, anosmia and hyposmia improve once doctors have treated the cause. In some cases, loss of smell can be permanent. If you notice symptoms of anosmia, it is important to seek treatment right away. Delaying treatment may result in permanent smell loss. Treatments may include changing medications, treating an infection (such as COVID-19), smell retraining therapy, or surgery to remove a blockage. Our world-renowned team has unparalleled expertise in smell disorders. Your care team will work with you to determine the most appropriate treatment plan. Let us help find personalized care options for you and your family. Symptoms **Anosmia and Hyposmia Symptoms** Signs of anosmia and hyposmia can come on suddenly or develop gradually. You may experience a change in your sense of smell before losing it completely. Familiar scents may smell different (parosmia), or you may detect odors that aren’t actually there (phantosmia). For some people, one of the first symptoms of anosmia and hyposmia is loss of taste (ageusia). You may notice that your food tastes more bland than usual. Or you can’t tell the difference between certain flavors and discover that your ability to smell has decreased. This happens because the sense of smell and sense of taste are very closely connected. To taste flavors, your brain combines the messages it receives about smell and taste. Causes **Causes of Anosmia and Hyposmia** Anosmia and hyposmia can affect people of any age or gender, but smell disorders are more common in men. These conditions can result from: - **Age**: After age 60, many people experience hyposmia, a reduced sense of smell. It’s rare to experience a complete loss of smell with age. - **Allergies and illnesses**: Nasal congestion and inflammation from allergies, influenza (flu), and the common cold can make it difficult or impossible to smell. - **COVID-19 and other viral infections**: Anosmia is a common symptom of COVID-19 and long COVID. Many other viral infections can also cause this condition. Usually, the sense of smell returns in a few weeks, but it can take months or even longer to return. - **Degenerative disorders**: [Alzheimer’s disease](https://stanfordhealthcare.org/medical-conditions/brain-and-nerves/alzheimers-disease.html), [Parkinson’s disease](https://stanfordhealthcare.org/medical-conditions/brain-and-nerves/parkinsons-disease.html), Lewy body dementia, and [multiple sclerosis](https://stanfordhealthcare.org/medical-conditions/brain-and-nerves/multiple-sclerosis.html) (MS) can damage odor receptors and cause smelling abnormalities. Hyposmia and anosmia are often early signs of these disorders. - **Genetics**: Rarely, people are born without the ability to smell. Doctors call this condition congenital anosmia. It results from certain genetic disorders, such as Kallmann syndrome, which also affects hormone development. - **Injury**: A [deviated septum](https://stanfordhealthcare.org/medical-conditions/ear-nose-and-throat/deviated-septum.html) (damage to the partition between the nasal cavities) can affect a person’s ability to smell. A traumatic brain injury can damage nerves in the brain responsible for communicating with olfactory nerves in the nose. - **Medications and chemicals**: Some drugs can cause anosmia, including antihistamines and nasal decongestants. The risk increases with long-term use of these medications. Exposure to toxic chemicals, such as insecticides, can also affect smell. - **Nasal polyps (noncancerous growths) and tumors**: Growths in the nose and sinuses can change how nerves work, resulting in anosmia. [Brain tumors](https://stanfordhealthcare.org/medical-conditions/brain-and-nerves/brain-tumor.html) can damage the area responsible for identifying smells. - **Radiation therapy**: People who receive radiation therapy for head and neck cancer may experience anosmia following treatment. - **Smoking**: Cigarettes and other tobacco products can affect the sense of smell, especially in people who have smoked for many years. Diagnosis **Anosmia and Hyposmia Diagnosis** Your doctor will review your medical history and ask about medications you’re taking. They will ask about your symptoms, including when they began, whether your taste is affected, and what type of symptoms you’re having, such as nasal congestion from allergies or an upper respiratory infection. Your doctor will examine you and look in your nose and throat. They may also recommend tests to confirm an anosmia diagnosis or rule out other conditions. These tests may include: - **CT scan, MRI, or other imaging studies**: These tests create detailed images of structures inside your head so that your doctor can spot any abnormalities or growths. They also help your doctor detect signs of degenerative disorders, such as Alzheimer’s disease. - **Nasal endoscopy**: For this test, your doctor inserts a thin, flexible tube with a camera down your nose. The camera shows your nasal and sinus passages. - **Olfactory nerve testing (smell testing)**: During this test, your doctor closes one nostril at a time and asks you to smell certain items, such as spices or coffee grounds. Your doctor may ask you to close your eyes, smell certain substances, and identify them based on how they smell.