What is Dysosmia?

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  • Written By: Donn Saylor
  • Edited By: John Allen
  • Last Modified Date: 26 September 2016
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Dysosmia is a neurological disorder that causes an altered sense of smell. The condition can manifest itself in a variety of ways: it may distort smells, which a sub-condition called parosmia; initiate no olfactory response at all, called anosmia; or produce smells that aren't there, called phantosmia. Since the oral cavity and the olfactory system are interrelated, some patients with dysosmia may develop issues with their sense of taste as well.

The three sub-conditions that comprise this type of olfactory dysfunction each possess their own respective set of characteristics and possible causes. Individuals with parosmia cannot properly identify smells, which is commonly presented as a neutral or pleasing scent being interpreted as an unpleasant one. The condition may apply to specific odors or any odor at all, depending on the pathology of the patient. Parosmia can be caused by several different conditions, including upper respiratory ailments, exposure to toxic chemicals, or various types of brain injuries.


Anosmia is distinguished by the inability to smell. Like parosmia, it can be specific to certain scents or can encompass any and all scents. With anosmia, the olfactory bulb is not triggered by the scent of the stimuli and no odor is detected. Anosmia can be the result of any number of conditions, including a blocked nose, infection of the sinuses, genetic predisposition, brain injury, Alzheimer's disease, or Parkinson's disease. It may also result from an overuse of certain types of nasal sprays, which damage neurons in the olfactory system.

Phantosmia can be characterized by smelling odors that do not come from a physical source. They are, in essence, hallucinations of the olfactory system, and, in most cases, are exceedingly unpleasant. Neurological disorders in which the neural pathways of the brain become twisted together are the most common causes for phantosmia. Epilepsy, schizophrenia, Alzheimer's disease, and head trauma can all lead to phantosmia.

Any of the three subsets of dysosmia can be diagnosed through a standard olfactory test administered by a specialist. In this screening, patients are given scented samples to smell and identify, and their responses are measured and recorded. The testing process, however, will not identify the cause of the disorder.

There is no definitive treatment for dysosmia. In some cases, the condition will go away on its own. Experiments in treating parosmia with the drug L-Dopa were conducted during the 1970s, but no conclusive results were reached. In the case of phantosmia, a surgery known as an olfactory epithelium has shown positive results in eradicating the condition.


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Post 3

@indigomoth - Well, I don't think the brain does it on purpose. These senses work through receptors and if the receptors are damaged then it's possible they are damaged on the "on" position, meaning that they are constantly believing that they are receiving stimulation. And I think with noise and smells alike that the more overwhelming they are, the more unpleasant they seem. I'm just speculating of course.

I read recently that they think they might be able to start growing back damaged cells in the inner ear, so maybe it won't be a problem for much longer. I don't know if they will be able to do the same thing for the nose or not, but I can't imagine it would be that different.

Post 2

I wonder why it seems like the default for the human brain, when something is malfunctioning, is for it to go to the most unpleasant kind of sensation. It would be awful to have olfactory hallucinations and to be constantly smelling something bad.

And the same thing happens sometimes with the ears. I've read about people who think they can hear constant noise and it's never pleasant noises, but always a cacophony that they find unbearable and that affects their concentration and sleeping patterns.

The brain can be cruel, I guess, but it just seems very counterproductive to me.

Post 1

My step-father has been told over and over by his doctor that he is going to end up with anosmia, because he won't stop using this particular kind of nasal spray that stops a runny nose.

The problem is that he is almost addicted to it, because whenever he stops using it he starts getting a runny nose again. Now he basically can't go without it, but he's killing his sense of smell.

That might not seem like a big deal, because there aren't that many wonderful smells. But it's something that you don't miss until you don't have it and smell also affects taste a great deal. I would hate to lose my sense of smell, just because I love the taste of food and a lack of taste and smell would be a great loss to me.

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