Is it true that your nose always smells bad to indicate illness?

There is a scientific basis for the statement that “a bad smell in the nose is a sign of disease”.
There are many reasons for this symptom, such as acute or chronic rhinitis, sinusitis, if the patient is a child, but also consider whether it is because of foreign objects in the nasal cavity.
Many patients with systemic diseases can also smell odors, such as diabetic ketoacidosis patients will have rotten apple smell when breathing.
There are many other reasons why the nose can always smell the odor, the specific causes are recommended to otolaryngology hospitals for examination, to identify the cause of the cause of the treatment under the guidance of a professional physician, do not take medication without authorization.