Anosmia (Loss of Smell)

Overview

Anosmia is a complete or partial loss of one’s sense to smell. Depending on the conditions, this loss of smell might be transient or permanent. Allergies and the common cold may irritate the nasal mucosa, resulting in a temporary loss of smell.

Severe brain or nerve problems like head trauma or brain tumors may affect one’s ability to smell indefinite. Anosmia is a condition that may develop as individuals age.

Although anosmia is seldom fatal, it may have a major influence on a person’s overall quality of life. Anosmia patients may lose interest in eating since they are unable to taste it sufficiently. As a consequence, weight loss or malnutrition may occur. Anosmia may induce unhappiness since it hinders the ability to smell or taste delicious things that might give comfort.

The sense of smell is critical for general health and nutrition, since diminishing feelings may result in decreased appetite and malnutrition, which is particularly prevalent in the elderly. Other health concerns may arise as a result of a diminished sense of smell. Individuals with anosmia may inadvertently ingest soured or rancid meals due to their inability to recognize aromas indicative of deterioration. Additionally, those who suffer from anosmia may be unaware that they are inhaling hazardous, filthy, or smoke-filled air.

Generally, treating the underlying issue will help restore the sense of smell. Antibiotics, for example, may assist in the treatment of sinusitis and related symptoms. If some medicines are impairing the sense of smell, switching medications may help alleviate the anosmia symptoms. If you have nasal polyps or another kind of blockage, surgery may be necessary.

Causes

A congested nose caused by a cold is a typical cause of a temporary, transient loss of smell that might last for days. Another frequent reason for congested nasal passages is a polyp or a nasal fracture, which obstructs the airways. Normal aging, especially beyond the age of 60, might result in the loss of smell. Sinus infection is the most common cause of loss of smell. Sinus infection is also associated with the complaint of a bad smell in the nose. Cold also results in loss of smell and taste.

In the nose and a location on the upper neck, there are several odor receptor-carrying cells. Each time they detect a scent, these smell receptors transmit a signal to the brain. The brain then distinguishes the different scents. Any difficulty with this process, such as a blockage, inflammation, stuffy nose, nerve injury, or an irregularity in brain function, may impair the ability to smell appropriately.

Following are the conditions that cause the issues with the inner lining of the nose along with congestion:

• Acute as well as chronic sinusitis
• Common cold
• Covid 19
• Allergic rhinitis i.e. hay fever
• Smoking
• Influenza

The following are conditions that are anosmia causes due to blockage or obstruction of airflow:

• Tumors
• Nasal polyps
• Deviated septum

The conditions that damage the nerves or brain’s ability to detect smell include:

• Alzheimer’s disease
• Diabetes
• Aging
• Multiple sclerosis
• Parkinson’s disease
• Traumatic brain injury
• Huntington’s disease
• Rhinoplasty

The sense of smell may return to normal within a few weeks or months.

Symptoms

Anosmia is a condition in which the sense of smell is lost or significantly reduced. This sensory impairment can present as anosmia symptoms that are frequently modest at first but become more prominent over time. Individuals suffering from anosmia may experience a reduced ability to sense scents or a complete inability to smell anything. The failure to notice strong and delicate odors, a changed sense of taste, and a failure to appreciate the aroma of meals, perfumes, or flowers are all common symptoms. In rare situations, patients may also experience a skewed sense of smell, perceiving foul or nonexistent odors.

Diagnosis

Anosmia is usually diagnosed using a combination of clinical evaluation, medical history, and specialized diagnostics. With a thorough assessment of the patient’s medical history, healthcare experts can seek for potential reasons such as viral infections, head injuries, or underlying medical disorders. A physical examination of the nose and sinuses may also be conducted to detect any structural abnormalities or obstructions. 

However, objective smell tests are frequently used for the most definite diagnosis. The Sniffin’ Sticks test, in which patients identify numerous odors presented in a controlled manner, or the University of Pennsylvania Smell Identification Test (UPSIT), which uses scratch-and-sniff cards to measure olfactory function, are examples of these tests. 

Imaging examinations, such as MRI or CT scans, may also be conducted to rule out structural abnormalities, such as nasal polyps or tumors, that could contribute to anosmia. Once anosmia diagnosis is done, the underlying cause can be identified, allowing for appropriate therapy or management.

Treatment

Congenital anosmia is a disorder for which there is currently no known treatment. Anosmia, on the other hand, is a condition that often resolves on its own. In the vast majority of cases, your sense of smell will return after the underlying issue has been remedied.

Anosmia treatment may be useful. If you have sinusitis or nasal polyps, for example, using steroid nasal sprays or drops may be therapeutic.

Certain individuals may benefit from a process called olfactory conditioning.

When To See A Doctor

Anosmia induced by flu, colds, and infections often resolve within a few days after beginning therapy. If your anosmia continues, you should consult with a medical expert. If you notice that you have lost your sense of smell, see a doctor. Consult your primary care physician if you are experiencing depression. Your doctor may recommend that you see an ENT specialist. Loss of smell should be communicated to the professional for avoiding the consequences. 

Summary 

Anosmia, or the loss of smell, affects approximately 3–20% of the population, with prevalence increasing with age. According to studies, 15% of adults over 60 experience some degree of olfactory dysfunction, and up to 50% of those aged 65–80 may suffer from impaired smell. This condition can be triggered by various factors such as allergies, colds, or sinus infections, and while often temporary, it can become permanent due to aging, head trauma, or neurological conditions like Alzheimer’s or Parkinson’s disease.

The impact of anosmia on quality of life is significant. According to research, 65% of anosmia patients report a loss of enjoyment in food, leading to reduced appetite and potential malnutrition. In addition, individuals with anosmia are at higher risk of accidents, as 50% report failing to detect dangerous odors, such as gas leaks or smoke. Furthermore, the link between anosmia and depression is well-documented, with up to 30% of those affected reporting symptoms of depression or anxiety due to sensory loss.

Diagnosis of anosmia typically involves clinical evaluation, medical history, and tests such as the University of Pennsylvania Smell Identification Test (UPSIT). According to a study, the UPSIT has a sensitivity rate of 90% in detecting olfactory disorders.

Treatment for anosmia depends on the underlying cause. For instance, anosmia related to sinus infections or nasal polyps can often be treated with medications such as steroids, while anosmia caused by viral infections, including COVID-19, has shown improvement in many cases through olfactory training, with studies indicating a 30–40% recovery rate within six months. Congenital anosmia, however, remains untreatable.

Disclaimer

This information is intended for educational purposes only and should not be considered a substitute for professional medical advice. If you have concerns about anosmia or any other medical condition, please see a doctor for an accurate diagnosis and personalized treatment suggestions.