One explanation for smelling burning when there is no apparent source is phantosmia, according to Mayo Clinic. This is a disorder in which the patient has olfactory hallucinations, which means they sense smells that are not really there.
There are several causes of phantosmia:
- A head injury.
- Upper respiratory tract infection.
- Damage to the brain as a result of seizures, Parkinson's disease, migraines, a brain tumor, stroke or sinusitis.
- Other neuropsychiatric disorders, such as depression and seasonal affective disorder.
Phantosmia produces different results for each patient. While some may smell burning, others may encounter different smells. As phantosmia sometimes indicates that a patient is suffering from a serious underlying condition, it is important to consult a doctor when it arises.
When trying to identify the cause of an olfactory disorder, the doctor usually takes a medical history that could reveal a physiological basis. If there is no reasonable explanation for the disorder, such as aging or drug use, then they may order a CT. When the patient's history is complex, an MRI is sometimes necessary.
Some doctors may also need to perform laboratory tests that analyze the patient's hormones, as they too can prevent the olfactory pathways from functioning normally. For example, patients with thyroid disorders also experience olfactory disorders.