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Causes and Symptoms of Parosmia

Causes and Symptoms of Parosmia

Parosmia is a smell disorder that causes an altered perception of smell. In this condition, an existing pleasant odor is wrongly perceived as offensive. This HealthHearty post shall delve deeper to understand the causes and symptoms of this olfactory disorder.
Nicks J
Did You Know?
The area of the brain that controls the sense of smell is known as the central olfactory system, which primarily consists of neural structures like piriform cortex and olfactory bulb.

Consider this: You painstakingly prepare a nice meal and serve it to your friend. You too are about to have the delicacies but all of a sudden your friend complains that the meal smells like rotten food. You are surprised to hear it since you don't find anything wrong with the meal. You confirm it after tasting the elaborate dishes. If there is no offensive or stinky odor, your friend probably might be suffering from parosmia, a condition marked by distorted sense of smell.
A person affected with parosmia, a smell disorder, is unable to perceive the natural odor of substances. The sense of smell perceives the odor as somewhat offensive. The odor that's actually not present is perceived, a common feature observed in parosmia patients. Thus in parosmia, the natural odor is distorted, making it foul. So if there is a particular odor, the affected person finds it different; he is unable to detect the expected aroma. People affected with parosmia have a hard time distinguishing between odors of different foodstuffs including dairy products, chocolates, vegetables and fruits.
Symptoms
This change in perception of odors associated with parosmia, makes it difficult to recognize the correct smell. So, distinguishing between different odors becomes next to impossible. Foul-smelling odor is one of the most common complaints among individuals affected by parosmia. The condition is typically marked by inability to recognize different smells, since every smell makes you feel sick as it is offensive, similar to that of vomit, rotten flesh, stools, and burnt food.
Causes
Our nose is able to detect and identify odor due to the presence of olfactory sensory neurons (OSNs). These are specialized sensory cells that lie in the nasal cavity and have receptors that recognize the smell in the air, which is relayed to the central olfactory system located in the brain. This is how we are able to identify a particular smell. However, when these OSNs get damaged, it can trigger symptoms of parosmia.
Following are the factors that may interfere with the normal functioning of olfactory sensory neurons:
Upper Respiratory Tract Infections (URTIs)
URTIs such as common cold, sinusitis, bronchitis, pharyngitis, pertussis, laryngitis, sore throat, and tonsillitis may cause functional changes in OSNs, which may lead to abnormal change in the perception of smell.
Head Injury
A head injury can damage that part of the brain which receives information transmitted from the olfactory sensory neurons. To be more specific, a head trauma can disturb the functioning of olfactory bulb and olfactory cortex that play an important role in detecting different smells. This can impair the ability to identify the sense of smell, leading to parosmia
Nasal Polyps
Nasal polyps refer to benign growths that erupt in the nasal cavity and sinuses. So the inside part of the nose may show fleshy swellings, which may lead to stuffy or runny nose. Since the OSNs are also located in the nasal cavity, formation of nasal polyps can affect their function, causing significant deviation in normal perception of smell.
Smoking
Here's another reason why smoking is detrimental to the health. If you don't kick the habit of smoking, you may eventually experience symptoms of parosmia. This is because cigarette smoking is known to interfere with sense of smell as many smokers continue to report about reduced ability to smell things correctly.
Medication
Aberrant odor perception can also occur due to intake of certain medications. For instance, there have been reports of antibiotic use for a few weeks causing impaired ability to smell.
Exposure to Harmful Chemicals
Inhaling fumes of dangerous chemicals, that include pesticides and certain solvents, can negatively affect the olfactory system of the body. These chemical fumes can damage the olfactory sensory neurons (OSNs), which may send wrong signals to the brain's smell-recognizing centers, leading to altered perception of smell.
Aging
The normal process of aging can also have a negative impact on the sense of smell. As we get older, our ability to smell and taste may decrease. One study has reported that around 24% of Americans over the age of 55 suffer from diminished sense of smell, whereas 27% of people above 80 complain about deficits in the sense of smell. So one cannot rule out age-related parosmia that makes it difficult to identify the natural odor.
Neurological Disorders
Neurological disorders like seizures that occur due to electrical disturbances in the brain, can also damage the areas of the brain involved in the identification of smell. So following a seizure attack, people may experience temporary olfactory impairment, leading to parosmia. Other neurological problems that can cause olfactory dysfunction include Parkinson's and Alzheimer's disease.
Treatment will depend on the underlying cause responsible for parosmia. Taking the right treatment as per the diagnosis of the underlying cause may help in restoring the perception of smell.
Disclaimer: The information provided in this article is solely for educating the reader. It is not intended to be a substitute for the advice of a medical expert.