Olfactory Aura Symptoms (Smell)
Type: Transitory aura symptom — typically develops gradually over 5–20 minutes and resolves within 60 minutes.
What is it?
Olfactory aura symptoms are temporary disturbances of smell that occur during a migraine aura. These can manifest as illusions (real smells perceived as something else) or hallucinations (smelling things that aren’t actually present). Unlike problems with your nose or sinuses, olfactory aura originates in the brain’s smell perception centers. These smell disturbances can occur in migraine but also occasionally in temporal lobe seizures, so medical evaluation is warranted if you experience this symptom. Parosmia (distorted smell) and phantosmia (hallucinated smell) are the two main types.
What it feels like
Smell disturbances during migraine aura develop suddenly and intensely. If you experience parosmia, a familiar smell suddenly transforms into something completely different — sweat might smell like beer, or a pleasant scent becomes repellent. The distortion is so vivid and wrong that you notice it immediately and may investigate whether something has actually changed in your environment. If you experience phantosmia, you smell something that isn’t there — commonly a metallic, burnt, rotten, or unpleasant odor. The hallucinated smell can be so strong that it feels overwhelming. These disturbances typically occur before or during the first part of a migraine and resolve as the headache pain develops.
Artwork depicting phantosmia: an apple representing the smell perceived during migraine aura — “I’d always smell apples before getting sick for some reason.”
How patients describe it
“But the weird thing is that certain smells are wrong during my aura, kind of like a odor hallucination. The one that I have been able to identify is that sweat/body odor will smell like beer. I do not know if other things smell wrong - considering it took me 8 years to figure the sweat/beer thing out.” — H.C.P.
“I have this sometimes as an aura or during my migraine. The only thing is that it took me almost 7 years of migraines to find this out. Most of the time the things that I smell I just assume are real. To me, when I am having such an episode, sweat/body odor smells like beer.” — H.C.P.
“I used to smell things that weren’t there and have things taste funny, too. This was back when my migraines were much worse. One night I was repeatedly awoken by the smell of freshly ground coffee. The smell was so strong I thought I might go crazy. It had disappeared by morning.” — P.H.B.
Subtypes
Parosmia
Distortion of real smells — something that actually smells one way is perceived as smelling completely different. For example, a pleasant smell might become repulsive, or familiar smells become unrecognizable.
Phantosmia
Hallucinated smells — perceiving odors with no actual source present. The most common hallucinated smells are unpleasant: burnt, rotten, metallic, or chemical scents. Pleasant smells are less common but do occur.
Related symptoms
- Gustatory disturbances (taste changes)
- Heightened sensitivity to other smells
- Nausea
- Other sensory auras
Clinical note
Olfactory aura symptoms are documented in migraine but can occasionally occur in complex partial seizure disorder. If you experience smell disturbances during migraine aura, medical evaluation is warranted to distinguish migraine from seizure disorders, particularly if symptoms are new, severe, or occur without other typical migraine symptoms. These disturbances do not indicate damage to your nose or olfactory system — they represent brain-based perception changes that resolve completely with the aura.
If this is the first time you experience these symptoms, or they feel different from previous episodes, seek medical evaluation to rule out other causes.