Can’t Smell: Don’t Blame the Virus Yet, These Are The Other Causes

19 May 2020

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We depend on our five senses to interact with and perceive the beauty of this world. All our senses are equally important, but for some reason, we tend to categorize our sense in order of most and least importance. Some do it consciously and willingly, while others aren’t even aware of it. We take care of the things that we think are more important. Similarly, we make sure that the sense we think is more important is protected, and in this process, we neglect the other unconsciously. 

The sense of smell is something that we are often least bothered about, isn’t it? And you just realized you’ve been doing it all along, didn’t you? Well, if it helps, you are not alone, most of us do it. However, we must stop not being bothered about it and start giving our smelling ability the care and importance it deserves. 

The sense of smell serves more purposes than you think it does. One of the most lesser-known facts about our olfactory function is that it’s closely related to our memory. There are so many times when we smell something and it evokes a particular memory or a feeling. The burning smell of the barbeque coal conjures up recollections of winter campfires, for example. In addition to being associated with memory, sense of smell is also highly emotive [1]. Therefore, we’ll be losing a lot if we lose the sense of smell. Yes! You read it right. We can lose the sense of smell. 

The condition in which one loses partial or complete sense of smell is called anosmia. It may be temporary or permanent depending on the cause. Common cold or allergies cause irritation in the nose’s lining that may lead to temporary anosmia. The condition isn’t usually serious but has a profound effect on a person’s quality of life. People with anosmia may lose interest in eating as they may not be able to fully taste the food. This can lead to other serious conditions and disorders like malnutrition, loneliness, anxiety, and even depression [2]. 

Causes Of Anosmia

Anything that has the potential to cause a disturbance in the path that leads to the perception of smell can lead to anosmia. Here are a few major causes of this condition.

Inflammatory and Obstructive Disorders: About 50% to 70% of the cases result from these. These two conditions include nasal and paranasal sinus disease. They cause inflammation in the mucosa (a lining in the nasal cavity) causing a direct obstruction [3].

Head Trauma: Another common cause of anosmia. Any kind of head injury can cause damage to the sinuses leading to a mechanical blockage and obstruction to the function of smell. An injury can also damage the olfactory axons, olfactory bulb, or the olfactory areas of the cerebral cortex – these are the parts that link the nose and the brain, and play a vital role in helping us smell things. The condition may be temporary or permanent depending on the area and the extent of the injury [3].

Aging: With age, individuals lose the number of cells in the olfactory bulb and the olfactory epithelium surface area, which are the most important components associated with the sense of smell. Aging decreases the sensitivity to smell that can eventually result in anosmia [3]. 

Disorders And Conditions: There are studies that link anosmia to neurodegenerative disorders like Alzheimer’s disease, Parkinson’s disease, and Lewy Body dementia; congenital conditions like Kallmann syndrome and Turner syndrome and infectious conditions like COVID-19 infections [3]. 

Lately, with the COVID-19 pandemic spread across the globe, people have been panicking about every minor symptom. Although losing the sense of smell is associated with the new coronavirus, it doesn’t necessarily have to mean that you’ve been infected. There are major symptoms that you are supposed to look for in this infection, and as far as your lack of smelling ability is concerned, it may be due to some other reason. 

Other Traumatic Or Obstructive Conditions: Toxic agents like tobacco and drugs can cause olfactory dysfunction, nasal or sinus deformity caused due to facial traumas, and many other obstructions that can lead to, or worsen the already existing anosmia. 

Some medicines such as beta-blockers, antithyroid drugs, dihydropyridine, ACE inhibitors, and intranasal zinc can also contribute to the possibility of one losing the sense of smell [3]. 

Treatment And Management

Managing and treating the condition depends on the severity of the condition. Medicines like antihistamines and systemic glucocorticoids can be given to patients with anosmia that is caused due to inflammation or obstructive diseases. Antibiotics like ampicillin are often prescribed for bacterial sinus infections. Surgical procedures are performed when the condition does not respond to conservative medical management.

There is no specific treatment for olfactory impairment that is caused due to any kind of damage in the olfactory neurons. However, these neurons have the ability to regenerate, but the time and degree of regeneration depend on the severity of the damage. The regenerative abilities differ from individual to individual and can span over the course of days to years. 

Reference: 

  1. https://www.fifthsense.org.uk/psychology-and-smell/
  2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5863566/
  3. https://www.ncbi.nlm.nih.gov/books/NBK482152/

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