hyposmia

Hyposmia is a reduced ability to detect odors, a form of olfactory dysfunction that is less severe than anosmia (complete loss of smell) and distinct from parosmia (distorted perception of odors). People with hyposmia may have difficulty detecting odors, identifying familiar scents, or perceiving the strength of smells. Impaired smell can also affect flavor perception and safety, such as the ability to notice smoke or spoiled food.

Causes are varied and include inflammatory and structural nasal conditions such as chronic rhinosinusitis and nasal polyps, allergic rhinitis, viral upper respiratory infections (including SARS-CoV-2), head trauma, aging, and neurodegenerative diseases such as Parkinson’s and Alzheimer’s disease. Other factors include smoking, environmental exposures, and certain medications.

Diagnosis typically starts with a medical history and nasal examination, followed by standardized smell tests to quantify olfactory function, such as the University of Pennsylvania Smell Identification Test or Sniffin’ Sticks. If results are unclear or other neurological concerns exist, imaging or referral to specialists in otolaryngology or neurology may be indicated.

Management focuses on addressing the underlying cause. Treatments may include nasal irrigation and intranasal corticosteroids for inflammatory disease, treatment of nasal obstructions, and smoking cessation. Olfactory training, involving repeated exposure to a set of odorants over several months, has some evidence of benefit. Prognosis is variable; many recover partially or fully after viral infections, while others experience persistent hyposmia, particularly with chronic or neurodegenerative conditions.

See also: Anosmia, Parosmia.