3.3.1 Causes and duration of olfactory dysfunction
Covid-19 infection was reported by 95 people as cause for their
olfactory dysfunction, closely followed by idiopathic reported by 90
people. Remaining causes in descending order were congenital (62),
post-traumatic head injury (61), viral infection other than Covid-19
(47), sino-nasal disorder (46), and other causes (36). Within other
causes, a myriad of aetiologies was mentioned including intracranial
lesions (e.g. meningioma and chondrosarcoma), iatrogenic (secondary to
brain/nasal operation), facial trauma and large doses of analgesia.
Roughly half of the respondents have had olfactory dysfunction for more
than 5 years (234), followed by 2-5 years (73), 1-2 years (63), less
than a year (54), and eight respondents were unsure of the duration.