Table 8

Investigation and management of change in smell

Investigations	Potential results	Clinical management plan
Actions from history, medication and dietary assessment
Medication findings	Chemotherapy related Opioid related	Reassure. Consider alternative medications. Consider referral to psychological medicine. Inform patient about the charity Fifth Sense.2
First line
Testing of the olfactory nerve	Neurological defect	Refer to neurology team.
	Olfactory hallucinations	Consider neurological referral. Consider referral to psychological medicine.
Blood test for zinc and vitamin B₁₂	Deficient	Arrange replacement.
Second line
Refer to ENT team	Eg, nasal polyps, sinus infection
CT/MRI head/PET	Base of skull disease	Refer to the appropriate MDT requesting an appointment within 2 weeks.
Third line
If normal investigations/no response to intervention		Reassure.

CT, computerised tomography; ENT, ear, nose and throat; MDT, multidisciplinary team; MRI, magnetic resonance imaging; PET, positron emission tomography.