Loss of Smell
Symptoms, Causes, Treatments, Questions & Related Topics

Top 4 Loss of Smell Causes

1. Nasal Congestion

Nasal congestion from a cold, flu, or allergies can often cause a temporary loss of smell.[1] If you’re sick or have a runny nose, excess mucus can block the scent receptors in your nose. Mild respiratory infections often clear up on their own, and your sense of smell usually returns after a few days. If you have seasonal allergies or another condition that leaves you regularly congested, you might need medical treatment to help clear your sinuses.

2. Nasal Obstruction

Obstructions like nasal polyps or deformities in your sinuses can block your sense of smell.[1] Unlike with a cold or allergies, a nasal obstruction might not cause a runny nose or excess mucus. If you have a nasal obstruction, you may feel stuffed up but can’t get relief from blowing your nose. Nasal obstructions can sometimes be treated with prescription pills or nasal sprays. In many cases, surgery is needed to remove or correct the obstruction.[2]

3. Aging

Your sense of smell can sometimes grow weaker as you age. Over time, the number of receptors in your nose can decrease, making you less sensitive to strong smells. Many people begin to have a weaker sense of smell after age 60, and more than 75% of people over 80 experience significant loss of smell.[3] Your doctor can perform tests to determine whether your loss of smell is a result of normal aging or a medical condition.

4. Brain and Nervous System Disorders

In some cases, the problem might be with your nervous system rather than your nose. Health conditions such as Alzheimer’s disease, brain tumors, Huntington’s disease, and Parkinson’s disorder can affect your sense of smell.[4] In these cases, there is usually nothing wrong with the scent receptors in your nose. Instead, your brain has trouble understanding the signals transmitted by the scent receptors. Notify your doctor if your loss of smell is accompanied by neurological symptoms like muscle weakness, seizures, or a decline in cognitive abilities.[5]

Possible Health Conditions Related to Loss of Smell

1. Sinus Infections

Sinus infections can cause nasal congestion and swelling, which may lead to a temporary or permanent loss of smell. While most people regain their sense of smell after their infection clears up, recurring infections can sometimes damage your sense of smell.[6] If you suffer from frequent infections and have noticed a loss of smell, you might need to see a specialist. An otolaryngologist, or ENT doctor - or your local urgent care center - can help you determine the cause of your infections and how to prevent future ones.

2. Sinus Disorders

Some sinus disorders cause chronic inflammation, which can interfere with your sense of smell. Chronic sinusitis can cause symptoms similar to those of a sinus infection. However, chronic sinusitis is usually not a sign of infection. Instead, it can be caused by a deviated septum, nasal polyps, enlarged turbinates, or other structural problems in your sinuses.[7] If you have sinus pain or congestion that doesn’t clear up on its own after a week or two, you might need to see a doctor. An ENT doctor can perform tests to determine the cause of your symptoms.

3. Allergies

Allergies can cause a runny nose, sneezing, congestion, and loss of smell or taste.[8] Many people with allergies also have watery eyes and some develop a rash. Your allergy might be due to many factors. Most people with allergies are allergic to pollen, dust, or animals. If you have allergies, you might notice that your symptoms are worse at certain times of the year. You might also have worse symptoms after you’ve been exposed to something you’re allergic to, like a neighbor’s dog.[8] An allergist, or a doctor who specializes in treating allergies, can help you find ways to manage your symptoms.

4. Dementia

A loss of smell is sometimes linked to dementia. While not everyone who loses their sense of smell goes on to develop dementia, it can be a risk factor. Many people with dementia report loss of smell as one of their earliest symptoms.[9] If other cognitive issues, such as poor memory, accompany your loss of smell, see a doctor. And if you’re a caregiver for a person with dementia, be sure to notify their doctor of any changes in the person’s sense of taste or smell.

5. Head Injuries

Head injuries can sometimes cause a temporary or permanent loss of smell.[10] A blow to the head can cause serious health complications. In some cases, it may even be life-threatening. It’s important to seek medical care for any head injuries, particularly those that led to a loss of consciousness.[11] If you are recovering from a head injury, let your doctor know right away if you experience any new symptoms, such as loss of smell.

Questions Your Doctor May Ask About Loss of Smell

  • When did you first notice a loss of smell?
  • Have you recently been sick?
  • Have you recently suffered a head injury?
  • Have you recently started a new medication?
  • Do you suffer from allergies or nasal congestion?
  • Do you have any cognitive conditions such as Alzheimer’s disease or dementia?

Loss of Smell May Also Be Known as

  • Ansonia
  • Hyposmia
  • Reduced sensitivity to odors


  1. Mayo Clinic. Loss of smell. https://www.mayoclinic.org/symptoms/loss-of-smell/basics/causes/sym-20050804
  2. John Hopkins Medicine. Nasal Obstruction. https://www.hopkinsmedicine.org/otolaryngology/specialty_areas/pediatric_otolaryngology/conditions/nasal_obstructions.html
  3. US National Library of Medicine. Effects of ageing on smell and taste. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2579627/
  4. WebMD. What is Anosmia? https://www.webmd.com/brain/anosmia-loss-of-smell#1-3
  5. Healthline. Brain Disorders. https://www.healthline.com/health/brain-disorders#types
  6. Mayo Clinic. Acute sinusitis. https://www.mayoclinic.org/diseases-conditions/acute-sinusitis/symptoms-causes/syc-20351671
  7. Mayo Clinic. Chronic sinusitis. https://www.mayoclinic.org/diseases-conditions/chronic-sinusitis/symptoms-causes/syc-20351661
  8. Mayo Clinic. Hay fever. https://www.mayoclinic.org/diseases-conditions/hay-fever/symptoms-causes/syc-20373039
  9. WebMD. Failing Sense of Smell Might Be Alzheimer’s Warning. https://www.webmd.com/alzheimers/news/20151116/failing-sense-of-smell-might-be-alzheimers-warning#1
  10. Merck Manual. Loss of Smell (Anosmia). https://www.merckmanuals.com/home/ear,-nose,-and-throat-disorders/symptoms-of-nose-and-throat-disorders/loss-of-smell
  11. US National Library of Medicine. Head injury — first aid. https://medlineplus.gov/ency/article/000028.htm

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