Loss of sense of smell can be from a cold, allergies, or an illness like COVID. Getting older can also affect your sense of smell. It is usually a temporary condition, but in some cases it can be a lasting problem.
7 most common causes
What happens when you lose your sense of smell?
Losing your sense of smell (called anosmia) can be upsetting and difficult to deal with. When you can’t smell, your sense of taste is also affected. Foods may seem bland and flavorless. It can even affect your appetite as food is no longer interesting to eat since they all taste the same.
A loss of smell can also be potentially dangerous. You may not be able to tell when food is spoiled and could make you sick. Or not smell smoke if there were a fire.
There are many conditions that can affect your sense of smell. Some of these conditions aren’t very serious, like colds and sinusitis. They can be treated with medication or may even go away on their own. And when your congestion clears, your sense of smell comes back. Losing your sense of smell is also sometimes a symptom of Covid-19. In some cases it can be a lasting symptom.
Your sense of smell can also become less sharp as you age. Though this may not be directly related to the aging process but from certain medications or underlying conditions that older people are more likely to have. And some people are born without the ability to smell. This is called congenital anosmia.
More serious causes of loss of smell include head or facial trauma or a brain tumor. These affect the nerves that connect the smell receptors to the brain. You may need surgery, but it may not bring back your sense of smell.
What causes anosmia
COVID-19 causes a variety of symptoms that range from mild to severe to life-threatening. For some people, not being able to smell or taste is one of those symptoms. Even if you don’t have symptoms that usually cause a loss of smell, like congestion. In some cases, not being able to smell is your only symptom of COVID-19.
Most people who have COVID-19 get back their sense of taste and smell. Treatment depends on the severity of your symptoms, and whether you are at home or need to be hospitalized. Treating COVID-19 may include taking medications or antivirals, monitoring your oxygen levels, or getting supplemental oxygen.
While most people who have COVID-19 fully recover, some people have long-lasting effects from the virus (sometimes called long-haulers), including feeling like their sense of smell and taste are not what they had been before they got sick.
It is thought that people can detect up to one trillion scents. Some people can detect more and others less. This number being so high is a testament to just how complex our sense of smell is and how so many different things can affect it. —Dr. Elizabeth Grand
2. Common cold
Most people get a cold (an upper respiratory infection) at least once a year. (There are over 200 viruses that can cause a common cold.) One of the most common symptoms is congestion—a stuffed-up nose can make you lose your sense of smell.
Symptoms usually run their course within a week. You can relieve your symptoms with over-the-counter pain medications and decongestants, which open up your nasal passageways to help you breathe better and regain your sense of smell.
- Loss of sense of smell
- Nasal discharge
- Sore throat
- Facial pain
- Tooth pain
- Ear pressure
Sinusitis, or a sinus infection, occurs when your sinus cavities in your face become infected with bacteria or viruses. The infection can cause the sinuses to swell and mucus to build up, interfering with being able to smell, and even breathe, through your nose.
Sinusitis is a common infection: Nearly 12% of adults are diagnosed with sinusitis each year, according to the Centers for Disease Control and Prevention (CDC). Most viral infections and some bacterial infections go away on their own.
At-home treatment includes rest, fluids, and taking fever and pain reducers like ibuprofen (Advil). But if symptoms last for longer than a week, you may have a bacterial infection. If you do, your doctor will likely prescribe antibiotics.
4. Nasal obstruction
- Loss of smell
- Trouble breathing through your nose
- Post-nasal drip
- Facial pain
A nasal obstruction is a blockage in your nose. The blockage may develop in your body’s tissues. For example, noncancerous growths called nasal polyps are often found in people with allergies. These can grow along the nasal lining and sinuses and reduce your ability to smell.
Cancerous growths can also develop in the nose, particularly in people with a history of smoking or from inhaled chemical exposure.
A deviated septum can also cause nasal obstruction and interfere with your sense of smell. It means that the cartilage of a person’s nose is not straight, which can cause one nostril and inner part of the nose to be larger than the other.
Your doctor may use a small camera device to look inside your nose to see if you have a blockage. Imaging tests may also be recommended. Treatment depends on the type of obstruction you have and may mean you need surgery.
- Loss of smell
- Runny nose
- Itchy, watery eyes
- Difficulty sleeping
- Post-nasal drip
Allergies are an overreaction by the immune system to something that doesn’t bother most other people. Allergy symptoms that primarily involve the nose are referred to as allergic rhinitis. When it causes congestion, you can lose your sense of smell.
Many people who have allergies are sensitive to pollen, but other things such as dust mites, animal dander, cockroaches, and mold can also cause reactions.
It can be hard to tell whether your symptoms are allergies or a virus, but there are a few differences. Generally, people with allergic rhinitis have a runny nose (with clear fluid). And you’re not likely to have fever or muscle aches, which can occur with colds or flu.
Allergies are diagnosed through testing, like a skin prick test or blood test. Your doctor may recommend over-the-counter or prescription allergy medication and nasal spray to control your symptoms. If your allergies are severe, you may need allergy shots (allergen immunotherapy).
6. Medication side effect
- Lost or decreased ability to smell
Certain medications can have the side effect in some people of affecting their sense of smell. They may have an effect on taste (which plays an important role in sense of smell) or may cause changes to the process of smell on a cellular level. These include:
- Certain antibiotics (amoxicillin, azithromycin, ciprofloxacin)
- Blood pressure medications (diltiazem, enalapril)
- Cholesterol medications (statins)
- Certain psychiatric medications
- Thyroid medications
- Nasal sprays
If you think your medication may be causing you to have trouble smelling things, talk to your doctor. They may want to switch you to a different medication. Usually, your sense of smell will return once you are no longer on the medication. But never decide to just stop taking medication without talking to your doctor first.
We take our sense of smell for granted since we use this sense constantly. Smell and taste are intimately related, and, often, if we lose our sense of smell then our sense of taste may also be disturbed. Loss of smell can have a profound impact on someone’s life as they may lose interest in eating, become malnourished, and even depressed. —Dr. Grand
7. Head trauma
Head trauma occurs from any type of physical damage to your head. Falls, such as from a ladder or in the bath, are the most common cause of head trauma.
Your sense of smell involves your nose, your brain, and the nerves that connect the smell receptors to the brain. A head injury can interfere with the pathway of these nerves, causing partial or complete loss of smell. This symptom may develop weeks or months after injuring your head.
Your doctor will do a neurological examination and may also order a CT scan or MRI of your head. Treatment of head trauma depends on the type of brain injury and may require surgery. In cases where there isn’t any detectable brain injury, brain rest (taking time off from work, doing only one task at a time, etc.) is recommended. Your sense of smell may return over time.
8. Brain tumor
- Loss of smell or taste
- Blurred vision
- Difficulty moving your limbs
- Difficulty speaking
Brain tumors can be benign (not cancerous) or malignant (cancerous). Some tumors start in the brain, while others develop when cancer in another part of the body spreads to the brain.
Tumors that are located in the part of the brain that includes the nerves responsible for smell and taste can interfere with and cause a partial or complete loss of these senses.
Your doctor will do a neurological examination and order imaging tests like a CT scan or MRI to diagnose a brain tumor. If the mass or tumor is benign, it may or may not be treated, but it will always be monitored closely by your doctor.
With treatment, like surgery or medication to decrease the size of the tumor, it is possible for the sense of smell to come back, but the loss of smell may be permanent.
If the tumor is malignant, treatment is essential. This involves some combination of surgery, radiation therapy, and chemotherapy, which is followed by physical and occupational therapy to help with recovery.
There are support groups and charities for people who suffer from long-standing loss of smell. Talking to people about your experience can be helpful in coping with your illness. —Dr. Grand
Other possible causes
There are many other conditions that can cause you to lose your ability to smell. These include:
How to treat loss of smell
- Saline nasal spray (to clear out nasal passages)
- Over-the-counter allergy medication
- Eating a well-balanced diet
Other possible treatments
- Prescription medication
- In-office diagnostic procedures, such as nasopharyngeal laryngoscopy and bronchoscopy.
- Smell training, also known as olfactory training, which involves sniffing the same specific scents every day (usually four) for several weeks. This is usually taught by an ENT (ear, nose, and throat), doctor, or nurse.
- Lifestyle modifications to adapt to loss of smell (such as learning how to detect life-threatening odors like gas leaks, spoiled food, and smoke).
When to call the doctor
Losing your sense of smell can be a sign of something serious. These are some of the reasons when you should call your doctor:
- You lose your sense of smell after a cold and it does not come back after a few weeks.
- Trauma or impact to your head or nose
- Difficulty breathing out of your nose
- You’re chronically tired.
- Losing weight without trying
- Vision changes
Should I go to the ER for loss of smell?
You should go to the ER if you have any of these signs of a more serious problem:
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