dysosmie

Dysosmia is an umbrella term for abnormalities of the sense of smell, including distorted odor perception and olfactory hallucinations. In clinical use, parosmia describes smells that are altered or distorted from their usual character, while phantosmia refers to odors perceived without any external source. Dysosmia can affect the quality of life, safety, and nutrition.

Symptoms vary. People with dysosmia may perceive common odors as unpleasant or grossly altered (parosmia), report that familiar scents no longer smell right, or detect smells that are absent (phantosmia). Smell distortions often accompany nasal or sinus disease, viral infections, or neurological conditions. Some patients notice triggers such as coffee, smoke, or cooking odors provoking abnormal smells.

Causes include post-viral olfactory dysfunction, chronic rhinosinusitis with or without nasal polyps, head trauma, allergies, and exposure to environmental toxins. Neurological disorders such as Parkinson's disease, Alzheimer's disease, or other neurodegenerative conditions can be associated with dysosmia. Medication effects and nutritional deficiencies have been reported in some cases.

Diagnosis relies on patient history and objective olfactory testing, such as threshold, discrimination, and identification tests (for example, Sniffin' Sticks or UPSIT). Imaging or referral to ENT or neurology may be indicated to identify underlying disease.

Management focuses on treating underlying conditions where possible. Olfactory training, a regimen of repeated exposure to a set of odors over several months, has evidence supporting improvement in olfactory function in some patients. Safety measures are important to reduce risk from impaired smell, such as installing functional smoke and gas detectors. Prognosis is variable; many cases improve gradually, but some persist for longer periods. See also parosmia and phantosmia.