Parosmia: Symptoms, Causes, Treatment

What are the symptoms of parosmia?

Parosmia is a type of olfactory dysfunction where a person experiences distorted smells. Here are the key symptoms associated with parosmia:

Distorted Smells: Common smells may be perceived as unpleasant, strange, or different from what they actually are. For instance, food might smell rotten or foul, or familiar scents might seem off.
Unpleasant Odors: Many people with parosmia report that smells they used to find neutral or pleasant now seem unpleasant or offensive.
Increased Sensitivity to Smells: There may be an abnormal sensitivity to smells, where normally mild odors become overwhelming.
Odor Confusion: Sometimes, the brain misinterprets smells, leading to confusion about what is being smelled.
Altered Taste: Since smell and taste are closely linked, parosmia can also affect taste, making foods taste strange or unpleasant.
Persistent or Intermittent Symptoms: Parosmia can be constant or come and go, depending on the underlying cause.

Parosmia can be caused by a variety of factors, including viral infections (like COVID-19), head injuries, neurological conditions, or exposure to certain chemicals. If you experience these symptoms, it’s important to consult a healthcare professional to determine the underlying cause and appropriate treatment.

What are the causes of parosmia?

Parosmia can arise from various causes, often related to issues with the olfactory system (the system responsible for the sense of smell). Here are some common causes:

Viral Infections: Respiratory infections, including those caused by the coronavirus (COVID-19), can lead to parosmia. Other viral infections, such as those causing the common cold or influenza, may also affect the sense of smell.
Head Trauma: Injury to the head or face can damage the olfactory system and lead to parosmia.
Neurological Disorders: Conditions like Parkinson’s disease, Alzheimer’s disease, and other neurodegenerative disorders can affect smell perception and cause parosmia.
Sinus and Nasal Conditions: Chronic sinusitis, nasal polyps, or other inflammatory conditions affecting the sinuses and nasal passages can interfere with the sense of smell.
Exposure to Chemicals: Prolonged exposure to certain chemicals, such as those found in cleaning products or industrial solvents, can damage the olfactory system and lead to parosmia.
Medications: Some medications can cause changes in taste and smell as a side effect.
Psychiatric Disorders: Certain mental health conditions, including some types of psychosis or mood disorders, may influence how smells are perceived.
Hormonal Changes: Hormonal fluctuations, particularly those associated with pregnancy or menopause, can sometimes affect the sense of smell.
Tumors: Rarely, tumors affecting the olfactory system or the brain can cause parosmia.

If you’re experiencing parosmia, it’s important to consult with a healthcare professional to determine the underlying cause and receive appropriate treatment.

How is the diagnosis of parosmia made?

Diagnosing parosmia typically involves a combination of patient history, clinical examination, and specific diagnostic tests. Here’s how the diagnosis is generally made:

Patient History: The healthcare provider will begin by taking a detailed history of your symptoms, including the onset, duration, and nature of the olfactory distortions. They will also ask about any recent illnesses, injuries, exposures to chemicals, or medications.
Clinical Examination: A physical examination may be performed to assess general health and to check for signs of sinusitis, nasal polyps, or other conditions affecting the nasal passages.
Olfactory Testing: Specific tests to evaluate your sense of smell may be conducted. These might include:

Sniffin’ Sticks Test: A test where you sniff different odorants and identify them.
University of Pennsylvania Smell Identification Test (UPSIT): A standardized test involving odor identification using scratch-and-sniff cards.

Imaging Studies: In some cases, imaging studies like a CT scan or MRI of the sinuses and brain may be ordered to identify any structural abnormalities, tumors, or other issues affecting the olfactory system.
Nasal Endoscopy: This procedure involves inserting a thin, flexible tube with a camera (endoscope) into the nasal passages to directly visualize the nasal cavity and identify any abnormalities.
Blood Tests: Blood tests may be conducted to rule out systemic conditions or infections that could be contributing to the olfactory dysfunction.
Neurological Examination: If a neurological cause is suspected, a neurological examination may be performed to assess overall brain function and detect any signs of neurodegenerative conditions.
Review of Medications and Chemicals: If exposure to chemicals or certain medications is suspected, the provider will review your exposure history and potentially adjust or discontinue the offending substances.

A multidisciplinary approach may be used, involving specialists such as otolaryngologists (ENT doctors), neurologists, and sometimes psychologists, depending on the suspected underlying cause of the parosmia.

What is the treatment for parosmia?

Parosmia, a condition where a person experiences distorted smells (often unpleasant), can arise from various causes, such as viral infections (including COVID-19), head injuries, or neurological disorders. Treatment aims to address the underlying cause and manage the symptoms. The effectiveness of treatment may vary depending on the severity and cause of the parosmia.

Here are the common treatment approaches:

1. Olfactory training:

Olfactory training is one of the most recommended treatments for parosmia. It involves smelling specific scents (typically rose, lemon, clove, and eucalyptus) twice daily for an extended period (several months). This method may help retrain the brain to recognize smells correctly.

2. Steroid treatment:

Oral or nasal corticosteroids: In cases where inflammation is believed to be contributing to the olfactory dysfunction, oral or nasal corticosteroids may be prescribed. These can help reduce inflammation in the nasal passages and potentially improve the sense of smell.

3. Zinc supplementation:

Zinc supplements: Some evidence suggests that zinc deficiency may contribute to olfactory dysfunction, so supplementation may be considered in cases of deficiency.

4. Treating underlying infections or conditions:

If parosmia is caused by an underlying condition, such as chronic sinusitis, a respiratory infection, or other illnesses, treating the root cause can help improve symptoms. For example:
Antibiotics for bacterial infections
Antivirals or supportive care for viral infections (e.g., post-viral parosmia following COVID-19)

5. Neurological treatments:

If parosmia is related to neurological conditions, such as a head injury or neurodegenerative disease, managing those conditions may improve the olfactory issues. In some cases, consulting with a neurologist may be necessary.

6. Surgical options (rare):

Surgery is generally not a common treatment for parosmia. However, in cases where there is a structural issue in the nose or sinuses (such as nasal polyps or tumors), surgery may be required to correct the underlying problem.

7. Coping strategies:

Avoiding triggers: Patients are often advised to avoid foods or smells that exacerbate the unpleasant sensations. Spicy or strongly scented foods might be avoided.
Mental health support: Because parosmia can affect quality of life, mental health support or counseling may help patients cope with the distress or anxiety related to the condition.

8. Medications (experimental):

Some medications that affect nerve signaling, such as gabapentin or antidepressants, have been explored in small studies to reduce the severity of smell distortions, although these are not standard treatments and may be used off-label.

Recovery from parosmia can be slow, especially if the condition was triggered by a viral infection or injury. Regular follow-up with an ENT specialist or neurologist may be necessary to monitor progress.