xRead - Olfactory Disorders (September 2023)

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INTERNATIONAL CONSENSUS ON OLFACTION

TABLE IX-15 Evidence for AR-related olfactory loss management with antihistamine therapy Study Year LOE Study design Study groups

Clinical end point Conclusions

SS-TDI

Compared with

Klimek

2017

3

Prospective multicenter observational

AR (persistent) (n = 47) MP-AZE/FP NS twice daily for 3 months

et al 231

baseline, there was significant improvement in OF

Stucket al 225

2015

1

Systematic review AR

Symptom scores BAST-24 VAS

There is limited evidence that antihistamines improveOF Compared with placebo, the

3 RCTs and 1 cohort study

Guilemany et al 1432

BAST-24 VAS

2012

2

RCT

AR(n = 27) Oral levocetirizine (5 mg every day) Placebo

levocetirizine group demonstrated significantly greater improvement in VAS only after 7 days baseline, there was no significant improvement in either group difference between the 2 treatment arms baseline, there was a significant increase in the number of symptom-free patients (smell loss)

Kalpaklioglu et al 1433

2010 2

RCT

AR(n = 62) AZENS Triamcinolone NS

Subjective symptom score (0–3)

Compared with

No significant

Wober

1997

4

Cohort

AR(n = 211 children) AZENS

Subjective symptom score (0–3)

Compared with

et al 1434

Gambardella et al 1435

1993

2

RCT

AR(n = 30) Oral loratadine Placebo

Subjective symptom score (0–3)

No difference

between the 2 treatment arms

AR = allergic rhinitis; AZE = azelastine hydrochloride; BAST-24 = Barcelona Smell Test-24; FP = fluticasone propionate; LOE = level of evidence; NS = nasal spray; OF = olfactory function; RCT = randomized controlled trial; SS = Sniffin’ Sticks; SS-TDI = Sniffin’ Sticks threshold, discrimination, identification combination; VAS = visual analog scale.

the central processing of odor-evoked neural activity. This activity arrives in the OB from primary olfactory sensor neurons, where it is processed locally and then distributed to five distinct cortical areas for further process ing: piriform cortex, olfactory tubercle, entorhinal cortex, amygdala, and anterior olfactory nucleus. 1479 The avail able clinical studies assess OF through subjective measures (eg, VAS or subjective symptom scores) and objective psy chophysical tests that include parameters such as forced choice identification, smell discrimination, and olfactory thresholds. 246 OD related to intracranial disease can be caused by structural lesions, such as the presence of tumors, aneurysms, and hemorrhages, or by surgical procedures

necessary to manage a structural lesion that in and of itself has not caused OD. 1480 Both transcranial approaches or endoscopic endonasal approaches have been associ ated with subsequent OD. 1480 In most studies, investigating olfaction following transcranial or endoscopic endonasal surgery, patients were treated with maintenance medical therapy (eg, intranasal corticosteroid). Recommendations for surgery to treat intracranial disease assume a risk of OD, and therapies for OD in this setting require further investigation. There are limited controlled trials investigating medi cal therapy for OD from intracranial disease, neurochem istry/neurotransmitter, or neurodegenerative disease. 246 Only post hoc cohorts were noted to improve in patients