Loss of Smell (Anosmia)

Loss of smell, also known as anosmia, is a condition where a person is unable to perceive smells. It can be temporary or permanent and can affect one or both nostrils.

Causes

• Viral infections: Such as the common cold, flu, and COVID-19, which can cause inflammation in the nasal passages and damage to the olfactory epithelium, leading to loss of smell.
• Nasal polyps: Growths that can block the nasal passages and reduce the ability to smell.
• Allergies: Such as hay fever, which can cause congestion and inflammation in the nasal passages, leading to loss of smell.
• Head injuries: Trauma to the head can damage the olfactory nerve, leading to loss of smell.
• Neurological disorders: Such as Alzheimer's disease, Parkinson's disease, and multiple sclerosis, which can affect the brain's ability to process smells.
• Certain medications: Such as antibiotics, antihistamines, and decongestants, which can alter the sense of smell.
• Aging: The sense of smell can decline with age, especially after the age of 60.

Symptoms

• Reduced or complete loss of ability to smell
• Distorted sense of smell (phantosmia)
• Decreased ability to taste food and drinks
• Nasal congestion or discharge

Diagnosis

Diagnosis is typically made through a combination of:

• Medical history
• Physical examination
• Smell tests (e.g. University of Pennsylvania Smell Identification Test)
• Imaging studies (e.g. CT or MRI scans) to rule out underlying conditions

Treatment

Treatment depends on the underlying cause and may include:

• Antibiotics for bacterial infections
• Steroids to reduce inflammation
• Surgery to remove nasal polyps or other obstructions
• Olfactory training (smell therapy) to help regain the sense of smell

Complications

Prolonged loss of smell can lead to:

• Nutritional deficiencies due to decreased appetite
• Safety risks (e.g. inability to detect gas leaks or spoiled food)
• Emotional distress and reduced quality of life