Yes. Just like many MS-related symptoms, the ability to smell can fluctuate when a scar of MS affects the part of the brain called the olfactory system. Recent MRI research suggests that loss of structural integrity of the olfactory system in MS patients is associated with difficulty in discriminating odors. There is also some evidence that smell difficulty is more common in secondary progressive MS than early MS. Many times, dysfunction in the sense of smell is subtle and not always noticed by patients.
A. Scott Nielsen MD