What are the types of smell disorders?
The olfactory epithelium is located in the uppermost part of the nasal cavity. The odor molecules must reach it with the air flow, contact the receptors, after which the signal is transmitted to the olfactory bulbs and the cerebral cortex. If swelling or polyps prevent air from reaching the receptors, they speak of a conductive disorder - it is often reversible. When the receptors or nerve pathways themselves are damaged, the disorder is called sensorineural. In addition to a decreased sense of smell, there are parosmia - distortion of odors - and phantosmia - the sensation of odors that are not there.
- Anosmia - complete loss of smell
- Hyposmia - decreased sense of smell
- Parosmia - distortion of familiar odors
- Phantosmia - non-existent smells
- Conductive and sensorineural disorders
- Congenital anosmia - rare
Possible reasons
The most common cause of sudden loss of smell is a viral infection, including influenza, ARVI and coronavirus infection: the virus damages the supporting cells of the olfactory epithelium. A gradual decrease in the sense of smell with nasal congestion is characteristic of chronic rhinosinusitis with polyps and allergic rhinitis. Traumatic brain injury can damage fine nerve fibers. As we age, our sense of smell naturally weakens. A decreased sense of smell can be an early sign of Parkinson's disease and Alzheimer's disease. Less commonly, the cause is drugs, toxic substances, tumors of the nose and brain.
- Viral infections, including coronavirus
- Chronic rhinosinusitis and nasal polyps
- Allergic rhinitis
- Traumatic brain injury
- Age-related changes
- Parkinson's disease and Alzheimer's disease
- Smoking, toxic substances, some medications
- Tumors of the nasal cavity and brain - rare
Associated symptoms
Along with the sense of smell, the perception of taste usually suffers: the tongue distinguishes only sweet, salty, sour and bitter, and the shades of taste of food are created by smell. Therefore, people with anosmia often complain that food has become bland. With polyps and sinusitis, loss of smell is accompanied by nasal congestion and discharge, and with allergies - sneezing and itching. After a viral infection, parosmia often appears, when familiar odors seem unpleasant. Impaired sense of smell due to memory impairment, tremors, or changes in handwriting requires consultation with a neurologist.
- Change in taste, bland food
- Nasal congestion and discharge
- Sneezing and itchy nose
- Distorted perception of smells
- Decreased appetite and mood
- Neurological symptoms - tremors, forgetfulness
What examinations are needed
The ENT doctor asks in detail about the onset of the disorder, past infections, injuries and medications taken, then examines the nose using an endoscope. Endoscopy reveals polyps, swelling and inflammation in the area of the olfactory cleft. To objectively assess the sense of smell, tests with a set of standardized odors are used. If chronic rhinosinusitis is suspected, a CT scan of the paranasal sinuses is prescribed. If there is no cause in the nose, the sense of smell is not restored, or there are neurological symptoms, an MRI of the brain is performed with an assessment of the olfactory bulbs and referred to a neurologist.
- Endoscopic examination of the nasal cavity
- Threshold tests and odor recognition
- CT scan of the paranasal sinuses
- MRI of the brain
- Allergy examination
- Neurologist consultation
Treatment and restoration of smell
Treatment depends on the cause. For chronic rhinosinusitis and polyps, nasal glucocorticosteroids are prescribed, sometimes short courses of systemic hormones; if ineffective, endoscopic surgery is performed. For allergic rhinitis, it is important to control allergies. After viral infection and injury, olfactory training has been proven to be beneficial: alternately sniff several strong scents, such as rose, lemon, clove and eucalyptus, twice a day for several months. Vitamins and supplements have not been confirmed to be effective. Treatment is prescribed by a doctor.
- Nasal glucocorticosteroids
- Endoscopic removal of polyps
- Control of allergic rhinitis
- Olfactory training for several months
- Quitting smoking
- Smoke and gas sensors at home, monitoring expiration dates of products
