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.