Loss of Smell

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.

5. Allergies

Symptoms

• Loss of smell
• Runny nose
• Congestion
• Itchy, watery eyes
• Sneezing
• Cough
• Irritability
• 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

Symptoms

• 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
• Chemotherapy

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.

7. Head trauma

Symptoms

• Loss of smell
• Headache
• Dizziness
• Confusion
• Blurred vision
• Nausea
• Vomiting
• Memory problems

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

Symptoms

• Loss of smell or taste
• Headaches
• Nausea
• Blurred vision
• Difficulty moving your limbs
• Seizure
• Confusion
• 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.

Other possible causes

There are many other conditions that can cause you to lose your ability to smell. These include:

• Aging, especially after age 60
• Nonallergic rhinitis
• Alzheimer’s disease
• Parkinson’s disease
• Multiple sclerosis
• Sarcoidosis
• Chemical exposures
• Smoking
• Cocaine use
• Nutritional deficiency