7 most common causes
What affects our ability to smell?
Loss of your sense of smell (called anosmia) can be alarming, especially lately because it’s one of the hallmark (noticeable) symptoms of COVID-19. But there are several other conditions that may affect your sense of smell.
Sense of smell may also fade a little with age, though this may be caused by certain medications or underlying conditions.
Some more serious causes 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.
COVID-19 causes a variety of symptoms that range from mild to severe to life-threatening. One of the more common complaints is the inability to smell or taste. You may not be able to smell even if you aren’t congested. It may also be your only symptom of COVID-19.
Because COVID-19 is contagious, it’s important to isolate yourself and talk to your doctor about next steps, which include getting tested for the virus. Your doctor can make the diagnosis using a nasal swab test, though you may also have saliva and blood tests.
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 hospitalized or at home. It may include monitoring your oxygen, receiving oxygen, or taking medications.
While most people who have COVID-19 recover fully, some people have long-lasting effects from the virus (sometimes called long-haulers) and others die from it.
We take our sense of smell for granted since we use this sense constantly. Smell and taste are intimately related, and, oftentimes, 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 because people may lose interest in eating and, as a result, become malnourished and even depressed. —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. A stuffed-up nose can make you lose your sense of smell.
Symptoms usually run their course within a week. You can ease 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.
3. Medication side effect
- Lost or decreased ability to smell
Certain medications have a risk of affecting your sense of smell. Some 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 a loss of smell, talk to your doctor, who may switch you to a different medication. Usually, your sense of smell will return when you are no longer taking the medication. But never stop taking medication on your own without talking to your doctor first.
- 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, such as 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).
- Nasal discharge
- Loss of sense of smell
- 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. It’s 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 such as ibuprofen (Advil). But if symptoms last for longer than a week, you may have a bacterial infection. Your doctor will likely prescribe antibiotics.
6. 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 be caused by a foreign object lodged in the nose (such as a bead) or it 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 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.
It is thought that people can detect one trillion scents. This number is variable, with some people being able to detect more and others being able to detect less. The fact that this number is so high is a testament to just how complex our sense of smell is and how so many different things can affect our sense of smell. —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. So a head injury may disturb 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 injury to your brain and may involve surgery. In cases where there isn’t any detectable brain injury, brain rest (taking time off 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 originate 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 these senses.
Your doctor will do a neurological examination and order imaging tests such as 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, such as 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. And there are many other people out there who have either gone through or are currently experiencing something similar. Talking to people about your experience can be helpful in coping with your illness. —Dr. Grand
When to call the doctor
Reasons to call your doctor include:
- You lost your sense of smell after a cold and it does not get better 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:
- Saline nasal spray (to clear out nasal passages)
- Over-the-counter allergy medication
- Eating a well-balanced diet
Other possible treatments
- In-office diagnostic procedures, such as nasopharyngeal laryngoscopy and bronchoscopy.
- Smell training, also known as olfactory training, which involves sniffing the same specific scents each 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 things such as gas leaks, spoiled food, and smoke)
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