Anosmie

Anosmia is the loss of the sense of smell, or a significant reduction in olfactory ability. It may be complete or partial and can occur on its own or together with changes in taste. The condition can be temporary or long-lasting, and its impact on safety and quality of life is a common concern.

Causes of anosmia are diverse. Conductive problems such as nasal obstruction from sinusitis, nasal polyps, or allergic rhinitis can block odorants from reaching the olfactory receptors. Inflammatory conditions and infections, including viral upper respiratory infections and COVID-19, are common triggers. Sensorineural causes include head trauma, exposure to neurotoxic substances, and certain medicines. Neurodegenerative diseases such as Parkinson’s disease and Alzheimer’s disease, aging (presbyosmia), congenital anosmia, and central nervous system lesions can also lead to smell loss.

Diagnosis typically starts with a detailed medical history and physical examination, followed by objective olfactory testing. Common tests include UPSIT or Sniffin’ Sticks assessments. Nasal endoscopy is used to evaluate obstruction or inflammatory disease. Imaging, such as CT for chronic sinus disease or MRI for suspected central causes, may be unnecessary in many cases but is used when indicated.

Management depends on the underlying cause. Treatments may include nasal saline irrigation and intranasal corticosteroids for inflammatory conditions, and surgical intervention for obstructive disease. Olfactory training, a structured program of repeated exposure to specific odors over several months, has shown benefit for some patients. Prognosis is variable: many recover after viral infections, while others—particularly those with structural or neurodegenerative etiologies—may have persistent anosmia.

Anosmia can affect safety, appetite, and quality of life, and ongoing research continues to explore effective therapies and rehabilitation strategies.