1
|
Anosmia and hyposmia
|
26.41 ± 7.99 days
|
VAS smell score using familiar substances with a distinctive odor
|
Mometasone furoate nasal spray in an appropriate dose of 2 puffs (100 μg) once a day
in each nostril for 3 weeks
|
31/50 (62%)
|
VAS smell score using familiar substances with a distinctive odor
|
Mometasone furoate nasal spray has no advantages over OT as a topical corticosteroid
therapy for the treatment of post-COVID-19 anosmia, which suggests that the pathogenesis
is neurological rather than local nasal inflammation
|
Diabetes
(the average time until recovery of the sense of smell was longer in diabetic patients
compared with non-diabetic ones)
|
2
|
Anosmia
|
97.37 ± 5.89 days
|
SST was used to assess the olfactory function by measuring 4 values: threshold (T),
discrimination (D), identification (I), and the augmented TDI
|
An intranasal spray of 1% sodium gluconate, 3 sprays for every nostril 3 times a day
for 1 month
|
20/25 (80%)
|
SST was used to assess the olfactory function by measuring 4 values: threshold (T),
discrimination (D), identification (I), and the augmented TDI
|
Intranasal sodium gluconate decreased elevated nasal calcium concentration
|
N/A
|
3
|
Anosmia
|
16.45 ± 1.28 days
|
SST was used to assess the olfactory function by measuring 4 values: threshold (T),
discrimination (D), identification (I), and the augmented TDI
|
An intranasal spray of 2% nitrilotriacetic acid trisodium salt three times daily for
1 month
|
N/A
|
SST was used to assess the olfactory function by measuring 4 values: threshold (T),
discrimination (D), identification (I), and the augmented TDI
|
Intranasal (NTA) can produce a calcium-NTA complex, which lowers the levels of calcium
cations in olfactory mucus
|
N/A
|
4
|
Anosmia
|
94.81 ± 3.89 days
|
SST was used to assess the olfactory function by measuring 4 values: threshold (T),
discrimination (D), identification (I), and the augmented TDI
|
An intranasal spray of 1% tetrasodium pyrophosphate, 2 sprays for every nostril 3
times a day for 1 month
|
26/32 (81%)
|
SST was used to assess the olfactory function by measuring 4 values: threshold (T),
discrimination (D), identification (I), and the augmented TDI
|
Intranasal tetrasodium pyrophosphate remarkably decreased nasal calcium levels
|
N/A
|
5
|
Anosmia and hyposmia
|
N/A
|
Anosmia and hyposmia were diagnosed based on the physician's decision and proper examination
of the nasal cavity and paranasal sinuse
|
220 mg zinc sulfate equivocal to 50 mg elemental zinc twice daily
|
N/A
|
N/A
|
Zinc therapy reduced the duration of recovery of olfactory function
|
N/A
|
6
|
Parosmia
|
More than 3 months
|
The degree of parosmia was assessed subjectively using the VAS, with scores from 0
to 10
|
3 platelet-rich plasma injections in the olfactory cleft at 3-week intervals
|
12/30 (40%)
(partial improvement= 9; complete improvement= 3)
|
The degree of parosmia was assessed subjectively using the VAS, with scores from 0
to 10
|
It has been shown that platelet-rich plasma promotes axon regeneration and restoration
of neurological functions after injury to the peripheral nerves
|
N/A
|
7
|
Parosmia
|
13.4 months
|
SST was used to assess the olfactory function by measuring 4 values: threshold (T),
discrimination (D), identification (I), and the augmented TDI
|
MOT with 3 sets of 4 different odors sequentially for 36 weeks. The training was applied
for 5 minutes twice a day
|
N/A
|
SST was used to assess the olfactory function by measuring 4 values: threshold (T),
discrimination (D), identification (I), and the augmented TDI
|
9 months of MOT helped the patients adjust and improve their scores on odor discrimination
tests, which enabled them to identify more odors correctly
|
N/A
|
8
|
Anosmia
|
19. ± 5.8 days
|
Anosmia was diagnosed based on the physician's decision. The degree of anosmia was
assessed through the VAS, with scoresfrom 0 to 10
|
Local Ivermectin in the form of nanosuspension mucoadhesive nasal spray (2 puffs per
day) for 3 months
|
47/49 (95.9%)
|
The degree of anosmia was assessed through the VAS, with scoresfrom 0 to 10
|
The direct virucidal effect of ivermectin on persistent viral particles or virions
on the nasal mucosa and olfactory bulb may be one of the possible mechanisms of treatment
|
N/A
|
9
|
Anosmia and hyposmia
|
9.7 + 2.5 months
|
SST was used to assess the olfactory function by measuring 4 values: threshold (T),
discrimination (D), identification (I), and the augmented TDI
|
PEA and luteolin
(a daily oral tablet that contained PEA 700 mg and luteolin 70 mg) for 1 month
|
N/A
|
SST was used to assess the olfactory function by measuring 4 values: threshold (T),
discrimination (D), identification (I), and the augmented TDI
|
PEA may reduce olfactory bulb inflammation by modifying microglia's polarization in
the M2 (name of one kind of macrophage) protective phenotype, promoting neural regeneration,
and even recovery of smell. Luteolin can block the polarization of bad microglia and
regulate transcription factors like STAT3, NF-κB, and AP-1, preventing brain cell
degeneration and reducing inflammation
|
N/A
|
10
|
Parosmia
|
Previously-trained group (PEA-LUT plus OT) = 8.8 ± 2.6 months;
training-naïve 1 (PEA-LUT plus OT) = 8.5 ± 1 months;
training-Naïve 2 (PEA-LUT alone) = 8.4 ± 1.7 months
|
SST was used to assess the olfactory function by measuring 4 values: threshold (T),
discrimination (D), identification (I), and the augmented TDI
|
Ultra-micronized PEA and luteolin (a daily oral tablet that contained PEA 700 mg and
louteolin 70 mg) for 3 months
|
N/A
|
SST was used to assess the olfactory function by measuring 4 values: threshold (T),
discrimination (D), identification (I), and the augmented TDI
|
PEA exerts an anti-inflammatory effect by modulating histamine release, reducing mast
cell degranulation, and activating M2 (name of one kind of macrophage) microglia,
which leads to the recovery of olfactory pathways. Luteolin shows anti-inflammatory
properties by reducing intracellular reactive oxygen species
|
N/A
|
11
|
Anosmia and hyposmia
|
More than 180 days
|
SST was used to assess the olfactory function by measuring 4 values: threshold (T),
discrimination (D), identification (I), and the augmented TDI
|
Ultra-micronized PEA-LUT plus OT for 3 months
|
32/45 (71.2%)
|
SST was used to assess the olfactory function by measuring 4 values: threshold (T),
discrimination (D), identification (I), and the augmented TDI
|
Ultra-micronized PEA-LUT modulates mastocyte activation and neuroinflammation process
|
N/A
|
12
|
Anosmia, hyposmia, and parosmia
|
8.8 ± 3.7 months
|
SST
|
Ultra-micronized PEA and luteolin (a daily oral tablet that contained PEA 700 mg and
luteolin 70 mg) for 3 months
|
Improvement rates were not reported for anosmia and hyposmia; however, 58/94 (61.7%)
cases with parosmia recovered
|
SST
|
Ultra-micronized PEA and luteolin is effective to treat brain neuro-inflammation,
which is the main responsible for quantitative smell disorders, but it has little
to no effect on peripheral damage (neuro-epithelial, olfactory nerve), which is the
cause of qualitative disorders
|
N/A
|
13
|
Anosmia and hyposmia
|
8.4 ± 2.9 months
|
SST was used to assess the olfactory function by measuring 4 values: threshold (T),
discrimination (D), identification (I), and the augmented TDI
|
Ultra-micronized PEA and luteolin (a daily oral tablet that contained PEA 700 mg and
luteolin 70 mg) for 3 months
|
120/130 (92%)
|
SST was used to assess the olfactory function by measuring 4 values: threshold (T),
discrimination (D), identification (I), and the augmented TDI
|
Ultra-micronized PEA and luteolin was supposed to enhance regeneration during OT by
lowering the level of COVID-induced neuroinflammation. The PEA component regulates
microglial polarization to a protective M2 phenotype, promoting neuronal repair and
smell recovery. Luteolin inhibits brain cell degeneration by preventing the polarization
of pro-inflammatory microglia
|
N/A
|
14
|
Anosmia and hyposmia
|
8.8 ± 3.4 months
|
SST was used to assess the olfactory function by measuring 4 values: threshold (T),
discrimination (D), identification (I), and the augmented TDI
|
Ultra-micronized PEA and luteolin (a daily oral tablet that contained PEA 700 mg and
Luteolin 70 mg) for 3 months
|
89.2%
|
SST was used to assess the olfactory function by measuring 4 values: threshold (T),
discrimination (D), identification (I), and the augmented TDI
|
Ultra-micronized PEA and luteolin could support the neuroplastic alterations of OT
by providing a more favorable regeneration environment. PEA-LUT's anti-neuroinflammatory
properties minimize inflammation in the olfactory bulbs and enable normal immature
neuron formation
|
N/A
|
15
|
N/A
|
3 weeks
|
SST
|
A: oral steroid course (14 days)
+ OT (16 weeks);
B: OT (16 weeks)
|
A: 43/78;
B: 26/53
|
SST
|
Steroids improve underlying upper airway inflammatory conditions which are not related
to the causative infection of olfactory loss
|
Contraindications for oral steroids (including uncontrolled diabetes, osteoporosis,
and high blood pressure)
|
16
|
N/A
|
12 to 24 months
|
SST + EEG
|
N/A
|
N/A
|
SST + EEG
|
N/A
|
N/A
|
17
|
N/A
|
3 to 12 months
|
UPSIT
|
A: theophylline -400 mg twice a day + nasal irrigations (6 weeks);
B: placebo + nasal irrigations (6 weeks)
|
A: 11/22;
B: 6/23
|
UPSIT
|
A phosphodiesterase inhibitor promotes neural olfactory signaling and sensory axonal
regeneration by preventing the breakdown of important secondary messengers cyclic
adenosine monophosphate and cyclic guanosine monophosphate
|
N/A
|
18
|
N/A
|
8.2 months
|
SST
|
A: topical administration of mometasone -100 µg twice a day + OT (3 months);
B: OT (3 months)
|
N/A
|
SST
|
N/A
|
N/A
|
19
|
Anosmia
|
Beyond 3 months after negative SARS-COV test
|
SST
+
obtaining nasal secretion to measure the concentration of calcium cations
|
A: 0.9% sodium chloride nasal spray (3 times a day for 1 month);
B: 2% DTPA nasal spray (3 times a day for 1 month)
|
N/A
|
SST
+
obtaining nasal secretion to measure the concentration of calcium cations
|
Calcium cations are necessary for smell transmission through an inhibitory feedback
inhibition approach, and DTPA can chelate calcium cations in an alkaline pH medium,
suggesting its use in patients with post-COVID-19 infection
|
N/A
|
20
|
Anosmia
|
2 weeks
|
VAS and the UPSIT
|
A: mometasone furoate 0.05% nasal spray (2 puffs twice a day for 4 weeks) + OT;
B: topical saline spray (2 puffs twice a day for 4 weeks) + OT
|
N/A
|
VAS and the UPSIT
|
N/A
|
N/A
|
21
|
Current olfactory loss
|
2 weeks
|
UPSIT
+
CGI-I self-report improvement scale); + ODOR olfaction-related quality-of-life questionnaire)
|
OT (sniff twice a day -for 3 months; 4 different odors)
|
Intervention:
56/240;
control:
5/35
|
UPSIT
+
CGI-I (self-report improvement scale) + ODOR (olfaction-related quality-of-life questionnaire).
|
N/A
|
N/A
|
22
|
Hyposemia and anosmia
|
N/A
|
UPSIT
+
CGI
|
Watch and wait for spontaneous recovery (for 6 months)
|
N/A
|
UPSIT
+
CGI
|
N/A
|
N/A
|
23
|
Persistent olfactory dysfunction
|
3 months
|
SST
|
OT (15.4 weeks)
|
Adhering to OT: 12/2;
not adhering to OT:
14/25
|
SST
|
N/A
|
N/A
|
24
|
N/A
|
At least 4 weeks
|
Brief Smell Identification Test
+
Taste Strips
+
self-rating of smell and taste function questionnaire
|
OT (12 weeks)
|
N/A
|
Brief Smell Identification Test
+
Taste Strips
+
self-rating of smell and taste function questionnare
|
N/A
|
N/A
|
25
|
Persistent olfactory dysfunction
|
200 days
|
Brief Smell Identification Test
|
Omega-3 fatty acid supplementation (2000mg daily- 6 weeks)
|
N/A
|
Brief Smell Identification Test
+
QOD-NS and SNOT-22
|
High levels of o mega-3 fatty acids are associated with neuro-regeneration and reduced
cellular inflammation
|
N/A
|
26
|
Anosmia and hyposmia
|
10.7 days
|
Butanol threshold
+
discrimination tests
|
A:
combination therapy – antihistamine and corticosteroid nasal spray (3 weeks);
B: antihistamine nasal spray (3 weeks);
C: corticosteroid nasal spray (3 weeks;
D: saline nasal spray (3 weeks)
|
N/A
|
Butanol threshold
+
discrimination tests
|
Reducing inflammation and edema due to reduced eosinophilic inflammation in the olfactory
region and improved symptoms of allergic rhinitis
+
antihistamines minimize the histamine-related cytokine storm
|
N/A
|
27
|
N/A
|
N/A
|
NRS scores for OD
|
A: Japanese traditional Kampo medicine;
B: Western medication
|
N/A
|
NRS scores for OD
|
Anti-inflammatory and immunomodulatory effects, enhanced circulation, and nerve protection
|
N/A
|
28
|
N/A
|
N/A
|
SST
|
A: combination therapy –prednisolone 40 mg a day + nasal drop betamethasone (2 weeks) + OT;
B: OT;
C: no treatment
|
N/A
|
VAS
+
SNOT-22
|
N/A
|
N/A
|
29
|
N/A
|
At least 4 weeks
|
VAS
+ UPSIT
|
A:
advanced OT (4 weeks);
B: classic OT (4 weeks)
|
N/A
|
VAS
+
UPSIT
|
Adding more scents cannot improve the OD
|
N/A
|
30
|
Anosmia
|
4.5 days
|
N/A
|
Intervention:
drop nasal betamethasone 3 times a day (maximim = 1 month);
Placebo:
drop sodium chloride 9% (maximum = 1 month)
|
83% of participants had recovered from anosmia (82% in the intervention group and
84% in the placebo group)
|
Self-report
|
Slower recovery in the intervention group shows that corticosteroids could impede
the regeneration of olfactory epithelium
|
N/A
|
31
|
Hyposmia, anosmia, and parosmia
|
60 days
|
SST
|
OT with oral and nasal corticosteroids, 60 days
|
N/A
|
SST
|
N/A
|
N/A
|
32
|
N/A
|
12 weeks
|
SST
|
Oral prednisolone treatment of 40 mg once a day for 10 days was received. The olfactory
function was evaluated 12 weeks after the start of the treatment
|
N/A
|
TDI, TST, ODQ, and self–reported with VAS
|
N/A
|
N/A
|
33
|
Hyposmia, anosmia, and parosmia
|
5 months
|
SST
|
Topical nasal corticoid, OT contains 4 international standard perfumes (rose, lime,
eucalyptus, and clove) which the patients smelled twice a day for at least 5 minutes
|
N/A
|
SST
|
N/A
|
N/A
|
34
|
Anosmia and dysgeusia
|
5 days
|
N/A
|
Fluticasone nasal spray and triamcinolone oral paste
|
N/A
|
N/A
|
N/A
|
N/A
|
35
|
Anosmia and hyposmia
|
40 days
|
CCCRC
|
Systemic prednisone and nasal irrigation with betamethasone, ambroxol, and rinazine
were administered for 15 days. Olfactory performance was evaluated on the 20th and
40th days.
|
N/A
|
CCCRC
|
N/A
|
N/A
|
36
|
Dysosmia
|
3.5 months
|
SST and the short version of the ODQ
|
Patients should perform OT with olfactory kits impregnated with dill, thyme, cinnamon,
cloves, coriander leaves, vinegar, cumin, lavender, coffee, vanilla, or mint twice
a day for 6 months
|
N/A
|
SST and the short version of the ODQ
|
N/A
|
N/A
|
37
|
Parosmia
|
12 weeks
|
SST
|
The patients were offered fragrances (lemon, rose, clove, and eucalyptus). Patients
must be exposed to each odor twice a day for 12 weeks.
|
N/A
|
SST
|
N/A
|
N/A
|