Introduction
Loss of smell is a common complaint in adults and yet has been
underestimated. Anosmia, complete loss of smell, is thought to affect at
least 1-5% of the population[1]. Based on European estimates,
anosmia is more prevalent than profound hearing loss or blindness in the
UK. Causes for olfactory loss are varied but the main diagnostic groups
include sinonasal disease (62%) and post-infectious olfactory
dysfunction (PIOD) (11%)[2]. Olfactory dysfunction has now emerged
as a key symptom in the coronavirus pandemic and it is possible we may
see a cohort of patients with lasting problems following the peak of the
Covid-19 impact[3, 4]. Historically, there is wide variation in
clinical practice reported by clinicians to patients on prognosis or
treatment[5]. Guidelines for the overall management of olfactory
disorders now exist in the Position Paper on Olfactory
Dysfunction[6] and recently the British Rhinological Society has
produced a consensus statement on managing Covid-related PIOD[7] but
the impact of those guidelines have yet to penetrate routine clinical
practice.
Previously published data has shown the high impact on quality of life
experienced by olfactory disorder patients, including depression,
anxiety, impairment of eating experience, feelings of isolation and
relationship difficulties[8, 9]. Most patients suffer a loss of
flavour perception which can adversely affect their appetite, but this
can be made even worse when parosmia is also present. Given the number
of potential treatment options for PIOD that have been proposed but yet
to undergo formal evaluation through a randomised clinical
trial[10], there is a pressing need to deliver more RCTs in this
area. A recent German study has highlighted Vitamin A as a potential
therapeutic agent for further evaluation[11]. In anticipation of
setting up a clinical trial to evaluate the role of vitamin A
intranasally for PIOD we sought to generate evidence of need to funders
through Public and Patient Involvement (PPI) in partnership with the
charity Fifth Sense that represents patients affected by Smell & Taste
disorders in the UK
(www.fifthsense.org.uk).
The aim of this study was to characterise the experience of patients
with PIOD in terms of the treatment they received in order to
demonstrate any unmet need.