The strange phenomenon of phantom smells
Phantosmia is the medical term for an imaginary odour (phantom smell). It is also known as an “olfactory hallucination”.
The smell is unique to the person and is usually unpleasant, spoiling the taste of any food or drink consumed.It can be in one or both nostrils.
Most phantom smells go away in time and are not caused by anything serious. But if the problem persists and you’re worried, see your GP.
There are a wide range of possible causes of phantosmia, which include:
Nasal infection – some people start to perceive a smell after they develop an infection that affects their nose or sinuses (read about sinusitis). The smell may become noticeable after a sudden change in airflow through their nose – for example, just after they’ve sneezed. It usually goes away when the infection clears.
Nasal polyps, which are abnormal tissue growths that form inside the nasal passages and sinuses (read more about nasal polyps).
Migraine with aura – some people smell phantom odours just before or during a migraine (read more about migraines)
Other possible causes are dental problems, smoking, exposure to certain chemicals such as insecticides or solvents, radiation for treatment of head and neck cancer and neurological (nervous system) conditions.
Less commonly, the cause of phantosmia is either nerve cells sending abnormal smell signals to the brain, or a problem with the brain itself.
How is it diagnosed?
Your GP will want to know if the problem is definitely with your sense of smell, and not with your sense of taste (it’s easy to confuse these).
They will also want to determine whether the smell is perceived, as in phantosmia, or actually real – you might be giving off and detecting a body odour, for example.
You’ll have a head and neck examination, to see if there is any obvious problem such as something in your nasal passages. The GP will want to know if the smell transmits through one nostril or both.
You may be referred to an ear, nose and throat specialist for further tests, which may include a nasal endoscopy, where a fine, flexible tube with a tiny camera at the end is inserted up through your nose and images are viewed on a television screen or an MRI scan or CT scan of your brain and nasal cavities, to rule out tumours, infections or obstructions
How is phantosmia treated?
Some people with phantosmia will find that the smell gradually fades over a few months, and no treatment is needed.
If it is caused by an illness such as sinusitis, it should go when you recover from the illness.