The Short Answer Educational content only. Any suspected concussion warrants medical evaluation. Persistent sensory symptoms after concussion warrant assessment by the appropriate specialist, an audiologist or ENT for hearing and sound symptoms, a neuro-optometrist or ophthalmologist for visual and eye symptoms, and a physician or neurologist to coordinate care. Consult a concussion-experienced clinician for individualized care. Phantosmia develops after concussion when damaged or regenerating olfactory pathways fire on their own, so the brain perceives a smell with no source present (Proskynitopoulos et al., 2016). Phantosmia is a phantom smell, an odor perceived in the absence of anything producing it, classically described as burnt, smoky, chemical, rotten, or metallic. After head injury it reflects aberrant, spontaneous activity in the injured or regenerating olfactory system, which the brain interprets as a smell that is not there. It is usually benign and often eases as the olfactory system settles, though a new phantom smell accompanied by other neurological symptoms warrants evaluation. Smell training and managing triggers support recovery. Phantosmia is a smell perceived with no source present. It reflects aberrant firing in the injured or regenerating olfactory system. It is usually benign and often eases as the system settles. What Phantosmia Is Phantosmia is the perception of a smell that has no external source, sometimes called an olfactory hallucination. The phantom odor is most often unpleasant, burnt toast, smoke, burning rubber, chemicals, rot, or a metallic smell, and it can come and go or persist, and be constant or triggered by certain situations. Phantosmia differs from parosmia, where a real smell is distorted, and from anosmia, the absence of smell. In phantosmia, the smell is generated internally with nothing there to cause it. It can be intrusive and distressing, particularly when the phantom smell is strong or constant. How Aberrant Olfactory Activity Produces Phantom Smells The sense of smell works by patterns of activity traveling from the olfactory receptors through the olfactory nerve to the smell-processing regions of the brain. Normally these fire in response to actual odor molecules. After head injury, the damaged or regenerating olfactory pathways can fire spontaneously, without any odor present, generating a signal that the brain reads as a smell. This aberrant activity can arise in the peripheral olfactory nerve as it regenerates or in the central smell-processing areas, and the brain, receiving a signal in the olfactory pathway, perceives an odor. Because damaged and regrowing nerve tissue is prone to firing abnormally, phantosmia often appears during the same recovery window as parosmia, and the two can occur together. Both reflect a disrupted olfactory system generating faulty signals, one distorting real smells and the other creating phantom ones. Why It Is Usually Benign but Sometimes Needs Evaluation Most phantosmia after concussion is benign, reflecting the injured olfactory system misfiring, and it commonly eases as the system settles and regeneration matures. Still, phantom smells can occasionally arise from other causes, including certain kinds of seizure activity in the temporal lobe, which processes smell, or other neurological conditions. This is why a new phantom smell, particularly one accompanied by other neurological symptoms such as altered awareness, unusual sensations, or changes in memory or behavior, warrants evaluation to exclude these causes. In the ordinary post-concussion context without such features, phantosmia is usually part of the sensory disruption of recovery. Symptom Presentation Perceiving a smell, often burnt, smoky, chemical, or metallic, with no source The phantom smell coming and going or persisting Onset during the recovery window, sometimes with parosmia Distress when the phantom smell is strong or constant No external odor that others can detect Usually benign, but sometimes with other neurological features Assessment An ENT specialist and a physician assess phantosmia by characterizing the phantom smell and confirming that no external source or nasal cause is present. The assessment distinguishes phantosmia from parosmia and looks for accompanying neurological features, since a phantom smell with altered awareness or other symptoms prompts evaluation for seizure activity or another cause, sometimes including imaging or other neurological testing. In the typical post-concussion case without such features, the phantosmia is placed in the context of olfactory recovery, and a physician monitors the course. Treatment Approach For benign post-concussion phantosmia, treatment focuses on supporting olfactory recovery and reducing the intrusiveness of the phantom smell. Smell training with distinct scents gives the olfactory system consistent real input and may help it settle. Reassurance that the phantom smell reflects a recovering system and usually eases reduces the distress, which itself can heighten attention to the smell. Practical strategies help while phantosmia persists. Some people find that rinsing the nose, breathing through the mouth briefly, or introducing a pleasant real scent can interrupt a phantom smell. Managing situations that seem to trigger it, and protecting sleep and reducing stress, which can worsen sensory symptoms, support recovery. When evaluation identifies a specific cause such as seizure activity, that cause is treated directly. Most benign phantosmia eases as the olfactory system settles over the recovery timeline, with a physician monitoring for any change that warrants further assessment. Sensory symptoms after concussion improve faster when the nervous system is regulated and the neck and autonomic system are addressed alongside specialist care. Start your 3-day free trial to build a supportive daily routine. Supporting Mobility Routine JME 155 Diaphragmatic breathing lowers the sympathetic drive that amplifies sensory sensitivity and steadies the nervous system. Ten slow breaths, several times daily. JME 14 Chin tucks reduce upper cervical tension that feeds headache, dizziness, and sensory overload. Ten repetitions with 5-second holds. JME 1 Cervical rotation restores segmental mobility and supports blood flow through the vertebral arteries to the brain. Ten repetitions per direction. JME 15 Cervical lateral flexion addresses side-bending restriction that sustains neck tension and sensory strain. Ten repetitions per side. JME 16 Cervical flexion and extension restore sagittal mobility restricted by suboccipital guarding. Eight slow repetitions. JME 2 Cervical retraction reinforces a neutral head position that reduces the postural strain feeding sensory symptoms. Ten repetitions per set. JME 150 Thoracic rotation restores mid-back motion needed for full diaphragmatic breathing and relaxed upright posture. Eight repetitions per direction. JME 227 Overhead reach opens the thoracic spine and rib cage, supporting the deep breathing that calms an overloaded nervous system. Ten repetitions with controlled tempo. Start your 3-day free trial for joint-specific mobility programming that supports the nervous system regulation behind sensory recovery after concussion. Common Mistakes Dismissing a phantom smell with other neurological symptoms without evaluation Confusing phantosmia with parosmia, which distorts real smells Letting distress heighten attention to the phantom smell Overlooking sleep and stress that worsen sensory symptoms Assuming all phantom smells are benign without considering other causes Progression Assessment confirms the phantom smell, excludes a nasal source, and checks for neurological features that would prompt evaluation for seizure activity or another cause. Benign post-concussion phantosmia is supported with smell training, reassurance, and practical strategies, and it usually eases as the olfactory system settles over the recovery timeline. Any concerning change prompts further assessment. What is phantosmia after a concussion? Phantosmia is a phantom smell, an odor perceived with no external source, often burnt, smoky, chemical, or metallic. After head injury it reflects aberrant, spontaneous firing in the damaged or regenerating olfactory pathways, which the brain interprets as a smell that is not truly there. Why do I keep smelling smoke or burning after my concussion? Damaged or regenerating olfactory pathways can fire on their own without any odor present, generating a signal the brain reads as a smell, and these phantom smells are often burnt or smoky. This aberrant activity arises in the injured olfactory nerve or the smell-processing brain regions during recovery. Is phantosmia after a concussion dangerous? Most phantosmia after concussion is benign, reflecting the injured olfactory system misfiring, and it usually eases over time. Still, a new phantom smell with other neurological symptoms such as altered awareness or unusual sensations warrants evaluation to exclude seizure activity or another cause, so concerning features should be assessed. How is phantosmia different from parosmia? In phantosmia the smell is generated internally with nothing there to cause it, a phantom odor. In parosmia a real odor source is present but perceived incorrectly, usually as unpleasant. Both reflect a disrupted olfactory system generating faulty signals, and they can occur together during recovery. Will phantosmia go away after a concussion? Benign post-concussion phantosmia usually eases as the olfactory system settles and regeneration matures over the recovery timeline. Smell training, reassurance, and managing triggers, sleep, and stress support recovery. Persistent or concerning phantosmia warrants assessment, and any identified specific cause is treated directly. Why Sensory Symptoms Happen After Concussion Sensory symptoms after concussion arise from disrupted sensory processing rather than damage to the sense organs alone. Concussion strains the connections between brain regions, alters the balance of excitation and inhibition, and leaves the nervous system in a sensitized, hyperexcitable state (Silverberg et al., 2020). In this state the brain turns up the gain on incoming signals, so ordinary light, sound, smell, taste, and touch are amplified, distorted, or perceived when absent. Some symptoms also reflect direct injury to sensory nerves. Most sensory symptoms improve over weeks to months as the brain recovers and the gain settles, and structured management speeds the process. Graded Exposure and Avoiding Overprotection A common trap in sensory recovery is total avoidance. Completely shielding from light, sound, or activity feels protective, but sustained avoidance makes the nervous system more sensitive over time, narrowing tolerance further. The better approach is graded exposure: staying within a tolerable range while gradually and deliberately increasing exposure as tolerance grows, never pushing far past the point where symptoms flare. This retrains the nervous system to accept normal sensory input. Extreme protection, such as constant dark glasses indoors or continuous earplug use, tends to worsen sensitivity and is used sparingly and strategically rather than continuously. Managing Sensory Overload Reduce competing sensory input by handling one channel at a time Take planned breaks in a calm, low-stimulation environment before overload builds Use diaphragmatic breathing to lower the arousal that amplifies sensitivity Pace demanding sensory environments rather than avoiding them entirely Protect sleep, since fatigue lowers sensory tolerance Treat coexisting headache, since pain and sensory sensitivity feed each other When to Seek Specialist Assessment Persistent or worsening sensory symptoms, symptoms that interfere with work or daily life, and any symptom with concerning features warrant specialist assessment. Hearing and sound symptoms are evaluated by an audiologist or ENT, who can test hearing and guide sound therapy. Visual and eye symptoms are evaluated by a neuro-optometrist or ophthalmologist. Smell and taste symptoms are evaluated by an ENT. A physician or neurologist coordinates care and excludes other causes. Pulsatile tinnitus, sudden vision or hearing loss, and rapidly worsening symptoms need prompt evaluation rather than watchful waiting. The Autonomic and Cervical Contribution Sensory symptoms rarely stand alone after concussion. Autonomic dysregulation keeps the nervous system in a heightened, sympathetic-dominant state that amplifies sensitivity, and cervical dysfunction feeds headache, dizziness, and sensory strain through shared brainstem pathways. Regulating the autonomic nervous system with diaphragmatic breathing and graded activity, and addressing the neck with mobility and manual therapy, lower the background arousal on which sensory symptoms ride. This is why calming the nervous system as a whole often eases sensory symptoms that specialist treatment alone does not fully resolve. References Proskynitopoulos, P. J., Stippler, M., & Kasper, E. M. (2016). Post-traumatic anosmia in patients with mild traumatic brain injury (mTBI): A systematic and illustrated review. Surgical Neurology International, 7(Suppl 15), S263-S275. PubMed Patricios, J. S., et al. (2023). Consensus statement on concussion in sport: the 6th International Conference on Concussion in Sport, Amsterdam, October 2022. British Journal of Sports Medicine, 57(11), 695-711. PubMed Silverberg, N. D., et al. (2020). Management of concussion and mild traumatic brain injury: a synthesis of practice guidelines. Archives of Physical Medicine and Rehabilitation, 101(2), 382-393. PubMed