Do you get an unpleasant smell even in the absence of bad odors? Are you more sensitive to an odor that does not bother other people? Chances are that you might be suffering with Dysosmia. Read on to know all about this nasal disorder, including its types, symptoms, causes, diagnosis and treatment.
It is an olfactory disorder that is related to a distorted sense of smell. In this condition, the olfactory system becomes dysfunctional due to which, patients may have difficulty in smelling or detecting any odor. Although not a serious disorder, it may lead to problems related to the sense of taste. This happens due to the fact that the nasal and oral chambers are interconnected.
Impaired olfaction can manifest itself in various sub-conditions which have their own set of characteristics and causes. These include:
It is generally manifested by insensitivity towards any kind of odor. It can either be acute or chronic, and can also be highly specific to certain odors. Hyposomia is a less serious form of Anosmia where patients have a reduced ability to smell and detect odors. The symptoms of various types of Anosmia may have different causes.
Also known as “Troposmia,” it is a condition in which patients misidentify odors. They not only find it difficult to distinguish between pleasant and unpleasant odors but may even fail to discriminate the taste between food and drinks. Sometimes, a neutral or pleasant odor may be interpreted as an unpleasant one.
In this particular dysfunction, patients usually hallucinate about smells. Here, unlike Parosmia, smelling of odors is not triggered by any physical stimulus. Due to this reason, these are referred to as “Phantom Odors”.
There are two major symptoms related to the impairment of smell.
Picture 1 – Dysosmia
Loss of olfactory function
Individuals suffering from this disorder cannot smell any odor in the environment. The sense of taste largely depends on the olfactory sense. Naturally, patients of this condition generally complain of a loss of taste sensation which is termed as “Ageusia”.
Distortion of olfactory function
Odors that are normally pleasant may smell odd or distorted. Natural odor is sensed as an unpleasant odor resembling that of a burned, rotting, fecal or chemical smell.
Dysosmia has a wide range of causes which can be classified on the basis of the different types of the condition.
Acute Anosmia is caused by blockage of the nose or infection of the nasal sinuses and nasal polyps. Prolonged use of medications, such as antihistamines and decongestants, often lead to nasal blockage. Structural defects, which include abnormal thinning or thickening of the mucus membrane inside the nose, may also lead to alteration of the sense of smell. On the other hand, the chronic form may occur due to complete damage of olfactory receptors neurons in the nose or injury in the brain that damages the olfactory nerve or some areas of the olfactory system. Due to this, there is a permanent loss of smell. Certain types of nasal spray, that cause vasoconstriction of the nasal chambers, may be responsible for causing damage to the olfactory receptor neurons. Degenerative brain disorders like Parkinson’s disease and Alzheimer’s disease are often characterized by this disorder.
Upper respiratory tract infections can cause damage to olfactory receptor neurons. Exposure to toxic substances like lead and other harmful chemicals, as well as to radiation can cause olfactory loss. This leads to an inability to transmit signals that represent a specific odor to the olfactory bulb. It is the olfactory bulb that processes information about odors. The condition may also arise if head traumas cause physical damage to the inferior side of the brain, where the olfactory bulb.
Epileptic seizures and disorders associated to the stem cells of the brain may stimulate the olfactory bulb, occasionally even in the absence of any external stimulus or trigger. It is defined as an olfactory hallucination which may result from neurological disorders like Alzheimer’s disease and Schizophrenia.
The initial diagnosis of this ailment involves a detailed elicitation of history. Physicians follow this up by asking questions to the patients to know about any prior upper respiratory infections or head injury.
Picture 2 – Dysosmia Image
Some of the main diagnostic techniques used in detecting this syndrome include:
University of Pennsylvania Smell Identification Test(UPSIT)
It involves use of four self-administered test booklets, each containing ten stimuli, for triggering smell. Patients pick one of the four booklets and are asked to detect all the types of odor. This method provides a rapid and easy way to quantify olfactory functioning and diagnose sinusitis as well as upper respiratory infection.
It is useful in diagnosing Parosmia and Anosmia. It comprises of three tests of olfactory function, that include
- Odor Threshold Test
- Odor Discrimination Test
- Odor Identification Test
These medical examinations help physicians measure graded stimulus and observe the response of patients. Peppermint sniffin stick is one kind of test where peppermint is placed in front of a patient’s nose. Some patients have reported of a foul or rotten smell in this test. Alcohol sniff test is another form of olfactory examination where patients are made to smell a material soaked in Isopropyl Alcohol.
In this procedure a beam of bright light is projected over the patient’s cheek or forehead in a dark room. If the sinuses are clear, a glow on the hard palate of the open mouth or in the areas of the cheek is observed.
Olfactory nerve testing
The function of the olfactory nerve is tested by blocking one of the nostrils and placing a pungent odor such as damp coffee essence under the open nostril. The test is repeated on the other nostril.
Nasal allergies like rhinitis can be diagnosed by this technique. Here, patients are asked to blow their nose on a piece of plastic wrap. The nasal discharge is then collected and sent for laboratory examination to detect the eosinophil (one type of white blood cells) count, which is primarily responsible for initiating allergy.
Other diagnostic techniques involve use of imaging tests like X-rays or CT scans. CT scan of the skull has now replaced the use of X-rays and is typically used to detect problems like:
- Bleeding within the brain
- Brain injury
- Inflammation in the paranasal sinuses
Previously, X-rays of the skull are generally performed to evaluate the fractures of the bone of the skull and detecting other conditions of the brain.
There are very few treatment options for this particular condition. Although treatment can restore the olfactory sense in some cases, the rate of recovery may actually vary depending on the type of olfactory dysfunction that a person is suffering from.
Treatment includes topical medications, systemic medications, and application of anesthesia to parts of the nose. In rare cases, endoscopic transnasal excision of olfactory epithelium is performed to treat phantosmia that may restore the olfactory function. Various experiments have been performed to treat parosmia with L-Dopa but with minimal success.
The prevention of this condition involves:
Avoiding head trauma
Certain precautions, such as wearing helmet, should be taken while playing outdoor games and driving a motorbike in order to reduce the risk of head injuries that might lead to Dysosmia.
Smoking and drinking should be strictly avoided as they might harm the delicate mucus membrane of the nose and make it susceptible to infections. People, who are allergic to particulate matter in air such as pollen or dander, should be extra-careful to avoid direct contact with these substances.
In most cases, Dysosmia is not a sign of a more serious health issue. Early diagnosis and cure may provide patients with faster relief from the symptoms of this disorder without any side effects.