Olfactory Hallucinations (Phantosmia): Smoke Smells Without Fire—ENT vs Neurology Pathways

Phantosmia is the perception of an odor in the absence of any external source. Many people describe a phantom smell of smoke, burning wires, chemicals, or rotten odors, although pleasant phantom smells also occur. Importantly, phantosmia is not the same as parosmia, where a real odor is distorted (for example, coffee smelling like gasoline).^[1]

Phantosmia belongs to the broader group of qualitative olfactory disorders, which are about odor quality rather than strength. People with phantosmia often worry about fires or gas leaks because the brain’s smoke/burn alarm is so primal—yet the cause may be a local nasal issue, a problem in the olfactory bulb, or a brain-level processing change.^{[1] [2]}

Phantosmia has two broad source pathways:

1. Peripheral (nose and sinuses)—issues in the nasal passages, olfactory epithelium, or sinuses can misfire odor signals. Typical culprits: viral or bacterial upper-airway infections, allergic or non-allergic rhinitis, chronic rhinosinusitis, nasal polyps, dental infections, or irritants such as smoke and solvents. After infections (including coronavirus disease), regenerating nerve fibers can rewire imperfectly, creating abnormal signals.^{[2] [3] [4]}
2. Central (brain)—conditions that alter olfactory processing may cause phantom smells: temporal lobe seizures, migraine, head injury, stroke, neurodegenerative diseases (for example, Parkinson’s disease), brain tumors, and psychiatric conditions. Certain medications can trigger or worsen smell disorders.^{[5] [6] [7]}

• Temporal lobe epilepsy can present with an olfactory aura—sometimes a sudden smell of burning or smoke—though olfactory auras are relatively infrequent in this epilepsy subtype. When present, mesial temporal structures, especially the amygdala, are often involved.^{[8] [9]}
• Sinonasal disease is the single most common category for smell disorders seen in primary care and ENT clinics, so many cases begin with a nose-first workup.^{[3] [10] [11]}
• Post-viral dysfunction (including post-COVID-19) remains a leading cause of qualitative olfactory symptoms, with olfactory training supported by growing—though mixed—evidence.^{[4] [12] [13] [14]}

Bottom line: If you smell smoke when there is none, both nose and brain causes are plausible—and your evaluation should be staged to rule out urgent issues while targeting the most likely source.

Call emergency services or go to an emergency department if phantom smells occur with any of the following:

• New, severe neurological symptoms: weakness, speech difficulty, facial droop, or a first seizure (possible stroke or seizure emergency).^{[6] [7]}
• Severe, abrupt headache (“worst ever”) alongside new smell hallucinations.
• Head trauma with persistent or worsening symptoms.
• Progressive neurologic change (for example, new memory loss, personality change) or cancer-type symptoms (unexplained weight loss, night sweats).^{[7] [10]}

Because sinonasal disease is common and treatable, many clinicians begin with ear, nose and throat (ENT) assessment:

1. Focused history and nasal exam
   Your doctor will ask about infection history, allergies, dental work, irritant exposure, medications, migraine, head injury, and recent viral illness. They will look for polyps, crusting, septal deviation, and signs of rhinosinusitis.^{[3] [10] [11]}
2. Nasal endoscopy
   A thin scope may be used in the clinic to visualize the olfactory cleft and sinus drainage pathways, increasing the chance of spotting subtle inflammation or polyps.^[11]
3. Objective smell testing
   Standardized olfactory identification tests (for example, “scratch-and-sniff” cards) help quantify loss, distortion, or normal thresholds, and can support referrals or follow-up.^[15]

4. First-line management if a nasal cause is suspected
   Evidence-based steps may include saline irrigations, topical intranasal corticosteroids, short courses of targeted antibiotics for acute bacterial sinusitis, and allergy control. Olfactory training—a structured, twice-daily smelling practice using distinct odors over weeks to months—can help patients with post-infectious or idiopathic qualitative symptoms.^{[3] [4] [12] [13]}

5. When ENT refers onward
   If endoscopy is normal, symptoms persist, or red flags appear, ENT may order sinus CT to assess hidden disease or—critically—refer to neurology for central causes and advanced testing.^{[11] [15]}

A neurology evaluation focuses on brain and nerve function:

1. Detailed neurologic history and examination
   Your neurologist will look for migraine features, seizure auras, cognitive changes, movement symptoms (for example, reduced smell with Parkinson’s disease), and focal deficits.^[6] [7]
2. Brain imaging and neurophysiology when indicated
   • Magnetic resonance imaging (MRI) of the brain if there are neurological signs, new persistent unilateral phantosmia, or concern for tumor, stroke, or structural causes.
   • Electroencephalogram (EEG) when a seizure disorder is suspected, especially with brief, stereotyped burning-smell spells and other temporal lobe features (déjà vu, rising epigastric sensation).^{[6] [8] [9]}
3. Management of central causes
   • Temporal lobe epilepsy: antiseizure medications; the presence of olfactory auras can guide localization but is uncommon overall.^[8]
   • Migraine: treating the primary migraine disorder (preventives, trigger management) often reduces olfactory aura-like symptoms.
   • Neurodegenerative disease: management targets the underlying condition; smell changes may be an early clue rather than a treatment target.
   • Psychiatric contributors: treating primary psychiatric illness can improve olfactory hallucinations.
   • Medication-related cases: adjusting or changing the offending medicine may resolve symptoms.^[7] [10]

Rare or last-resort interventions: Small case series describe topical anesthetics or even surgical ablation of olfactory mucosa for severe, intractable phantosmia, but benefits are inconsistent and risks are significant; these approaches are not standard and are reserved for select cases in specialist centers.^[1]

A practical, symptom-driven approach:

• Start with ENT if you have recent or chronic nasal symptoms (congestion, drip, facial pressure, allergy), recent viral illness, dental problems, or if your phantom smell changes with sniffing or nose position. Sinonasal and post-viral causes are common—and often treatable.^{[3] [10] [11]}
• Go to Neurology sooner if episodes are brief and stereotyped (seconds to a minute), possibly accompanied by déjà vu, rising stomach sensation, automatisms, awareness changes, or if there are new neurological deficits, head trauma, severe headaches, progressive cognitive or movement symptoms, or red flags described above.^{[6] [8]}

In reality, collaboration is common: ENT rules out or treats peripheral problems; Neurology assesses central pathways if symptoms persist or the history points that way.

• Sinonasal disease: saline rinses, intranasal corticosteroids, treatment of infection when confirmed, allergy control, and polyp management can reduce abnormal odor signaling.^{[3] [10]}
• Post-viral dysfunction: olfactory training is safe, inexpensive, and supported by growing evidence (meta-analyses suggest benefit, though results vary by protocol and timing). Newer studies are exploring adjuncts like transcranial direct current stimulation combined with olfactory training, but these remain specialized.^{[12] [13] [14]}
• Neurological causes: antiseizure medications for epilepsy; migraine prevention and acute care; disease-specific care for neurodegenerative conditions.^{[8] [9]}
• Medication-induced cases: review your medication list; if a temporal link exists, your clinician may adjust the regimen.^{[7] [10]}

There is no universal drug that reliably stops olfactory hallucinations across causes. Small reports suggest variable responses to agents like haloperidol; these are not routine and must be weighed against side effects.^[1]

Only for refractory, severely disabling phantosmia after exhaustive workup—options like olfactory mucosa ablation have been tried in limited series, with inconsistent and sometimes only temporary benefit.^[1]

• Safety first: Install and regularly test smoke detectors and gas leak detectors so you are not constantly second-guessing the environment.
• Trigger diary: Track time of day, stress, foods, sleep, and exposures; patterns can suggest migraine, reflux, or irritant links.
• Saline nasal irrigation: Daily or twice-daily saline rinses can improve mucus flow and reduce inflammatory triggers in the olfactory cleft.^[3]
• Structured olfactory training: Twice daily, spend ~20–30 seconds smelling four distinct odors (for example, rose, eucalyptus, clove, lemon) for at least 12 weeks. Rotate odors every 12 weeks. Patience matters; improvement is gradual. Evidence is strongest for post-viral cases but it is reasonable to try broadly given its safety profile.^{[12] [13] [14]}
• Sleep, stress, and migraine hygiene: Regular sleep, hydration, meals, and stress management can lower neurologic triggers.
• Avoid irritants: Tobacco smoke, solvents, and heavy fragrances can exacerbate symptoms during recovery.

Is phantosmia dangerous by itself?

Phantosmia is a symptom, not a disease. Many causes are benign or self-limited, especially after infections. That said, because neurologic causes exist, a basic workup is wise—particularly with red flags or if symptoms persist.^{[6] [7]}

Why does the phantom smell so often seem like smoke or burning?

Our olfactory system is closely tied to threat detection. When misfiring circuits generate “noise,” the brain may default to salience-heavy odors (smoke, burning, gas) that usually signal danger. This is a common patient report and fits with how olfactory memory and limbic circuits interact.^{[6] [8]}

How long does it last?

Duration varies. Post-viral cases may improve over weeks to months, especially with olfactory training. Neurological or sinonasal causes follow the course of the underlying condition.^{[12] [13]}

Can smell testing really help?

Yes. Objective olfactory tests document baseline function, guide referrals, and help track improvement, which is especially useful for insurance, research-based care, or complex cases.^[15]

1. Rule out a real hazard (check home, confirm with others, use detectors).
2. Book an ear, nose and throat (ENT) visit if you have any nasal or sinus symptoms—or if you are unsure where to start.
3. Begin saline irrigations and olfactory training unless your clinician advises otherwise.^{[3] [12]}
4. Escalate to neurology promptly if you notice brief, stereotyped episodes or neurologic symptoms, or if ENT evaluation is unrevealing and symptoms persist.^{[6] [8]}
5. Follow through on imaging or EEG when recommended to exclude central causes.
6. Track progress with a symptom diary and repeat smell testing as advised.^[15]

Phantosmia is usually manageable and often improves, especially when the evaluation follows a nose-first, brain-next pathway—and when you combine targeted medical care with daily olfactory training and sensible at-home strategies. If your phantom smoke smells are new, frequent, or paired with neurological symptoms, get checked promptly so the right specialty—ear, nose and throat (ENT) or neurology—can take the lead at the right time.