Olfactory Hallucinations (Phantosmia): Causes, Evaluation, and When to Seek Help

Phantosmia (olfactory hallucination) is perceiving smells that aren't present. "Olfactoreal malaise" is not a recognized medical term.

Common Causes

• Neurological: Temporal lobe epilepsy, Parkinson's, Alzheimer's, MS, stroke, brain tumors.
• Sinonasal: Chronic sinusitis, nasal polyps, post-viral olfactory loss (parosmia/phantosmia).
• Trauma: Head injury damaging olfactory pathways.
• Medications: Certain antibiotics, antihypertensives, antidepressants.
• Psychiatric: Schizophrenia, depression (less common).
• Toxic exposure: Solvents, heavy metals.

Characteristics

• Often unpleasant: burning, rotten, fecal, chemical, smoke.
• Unilateral or bilateral; constant or intermittent.
• May precede seizures (aura) or migraines.

Evaluation

1. Detailed history: onset, triggers, quality, laterality, associated symptoms.
2. Nasal endoscopy + smell testing (UPSIT, Sniffin' Sticks).
3. Neuroimaging (MRI brain + olfactory bulbs) if neurological signs or persistent.
4. EEG if seizure suspicion.

Management

• Treat underlying cause (sinusitis, medication adjustment, seizure control).
• Saline rinses, topical anesthetics (lidocaine), gabapentin for refractory cases.
• Olfactory training (essential oils) for post-viral dysfunction.

See a neurologist or ENT if phantosmia persists >2 weeks, worsens, or accompanies other neurological symptoms.