Background The amelioration of the current COVID pandemic relies on swift and efficient case finding as well as stringent social distancing measures. Current advice suggests that fever or new onset dry cough are the commonest presenting complaints. Methodology We present a case report and case series as well as other evidence that there is an important fourth presenting syndrome, namely isolated sudden onset anosmia (ISOA), which should be considered highly suspicious for SARS-CoV-2. Results A patient presenting with ISOA who went on to test positive for infection with COVID-19 and did not develop any further symptoms as well as a case series of similar patients although limited by the lack of reliable testing at the moment. Conclusions We posit the existence of a fourth common syndrome of COVID-19 infection: isolated sudden onset anosmia (ISOA) and urge the international community to consider this presentation in current management advice.

Isolated sudden onset anosmia in COVID-19 infection. A novel syndrome?

Objectives/Hypothesis: The aim of this study was to evaluate the effects of olfactory training (OT) on olfactory function in patients with persistent postinfectious olfactory dysfunction (PIOD). Study Design: Randomized, single-blind, controlled, multicenter crossover study. Methods: Twelve tertiary university medical centers participated. Investigations were performed at three visits (base- line, after 18 weeks, and after 36 weeks), including only subjects with PIOD of <24-months duration. At each visit, partici- pants received detailed assessment of olfactory function. Seventy subjects trained with high concentrations of four odors for 18 weeks; the other half (n 5 74) trained with low concentrations of odors. For the following 18 weeks this regimen was switched. Results: After 18 weeks, olfactory function improved in the high-training group in 18 of 70 participants (26%), whereas only 11/74 improved in the low-training group (15%). In subjects with a duration of olfactory dysfunction of <12 months, olfactory function improved in 15/24 participants (63%) of the high-training group and in 6/31 participants (19%) of the low-training group (P 5.03). Conclusions: OT improves PIOD, and the use of odors at higher concentrations is beneficial to improvement. OT is a safe procedure and appears to be particularly useful in patients who start OT within 12 months after the onset of the disor- der. OT is the first successful therapy regime in patients with PIOD.

Olfactory training is helpful in postinfectious olfactory loss: A randomized, controlled, multicenter study

Anosmia and hyposmia, the inability or decreased ability to smell, is estimated to afflict 3-20% of the population. Risk of olfactory dysfunction increases with old age and may also result from chronic sinonasal diseases, severe head trauma, and upper respiratory infections, or neurodegenerative diseases. These disorders impair the ability to sense warning odors in foods and the environment, as well as hinder the quality of life related to social interactions, eating, and feelings of well-being. This article reports and extends on a clinical update commencing at the 2016 Association for Chemoreception Sciences annual meeting. Included were reports from: a patient perspective on losing the sense of smell with information on Fifth Sense, a nonprofit advocacy organization for patients with olfactory disorders; an otolaryngologist's review of clinical evaluation, diagnosis, and management/treatment of anosmia; and researchers' review of recent advances in potential anosmia treatments from fundamental science, in animal, cellular, or genetic models. As limited evidence-based treatments exist for anosmia, dissemination of information on anosmia-related health risks is needed. This could include feasible and useful screening measures for olfactory dysfunction, appropriate clinical evaluation, and patient counseling to avoid harm as well as manage health and quality of life with anosmia.

Anosmia-A Clinical Review.

Smell and taste disorders can markedly affect the quality of life. In recent years we have become much better in the assessment of the ability to smell and taste. In addition, information is now available to say something about the prognosis of individual patients. With regard to therapy there also seems to be low but steady progress. Of special importance for the treatment is the ability of the olfactory epithelium to regenerate.

Smell and taste disorders.

Background
Olfactory loss is a challenging clinical problem with few proven therapeutic options. Early experimental results with olfactory training suggest that this novel therapy may be an effective intervention for olfactory dysfunction of multiple etiologies. The aim of this study was to systematically review currently available studies that assess the efficacy and outcomes of olfactory training in patients with olfactory loss.

Methods
A comprehensive systematic literature review was performed with the assistance of a reference librarian using the PubMed, PsycInfo, Google Scholar, EMBASE, and Proquest databases. Eligible studies were extracted based on defined inclusion criteria and the effect of olfactory training on objective olfactory function was evaluated qualitatively and by meta-analysis.

Results
A total of 10 studies with 639 patients were identified and systematically reviewed. Sufficient data for meta-analysis was available for 3 studies. Patients receiving olfactory training experienced a statistically significant improvement in the Threshold, Discrimination, Identification (TDI) score compared to control patients (mean difference [MD] 3.77; 95% confidence interval [CI], 2.28 to 5.26). Improvement in olfactory function was observed in discrimination (MD 1.92; 95% CI, 1.13 to 2.71) and identification (MD 1.61; 95% CI, 0.55 to 2.68), but not in olfactory thresholds (MD −0.01; 95% CI, −0.42 to 0.39).

Conclusion
Olfactory training is a promising modality for the treatment of olfactory dysfunction. Results of this systematic review and meta-analysis suggest that it may be an effective treatment for olfactory dysfunction due to multiple etiologies. Additional high-quality studies are needed to define indications, outcomes, and duration of therapy for this novel therapy.

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Efficacy of olfactory training in patients with olfactory loss: a systematic review and meta-analysis.

Objectives:
Olfactory function is known to be modulated by repeated exposure to odors. The aim of this investigation was whether patients with olfactory loss would benefit from “Training” with odors in terms of an improvement of their general olfactory function. It was hypothesized that olfactory Training should produce both an improved sensitivity towards the odors used in the Training process and an overall increase of olfactory function.

Study Design:
The prospective study was performed in patients with olfactory dysfunction.

Methods:
One group of patients performed the Training (n = 40), whereas another part did not (n = 16). Exclusion criteria for patients were sinunasal disease. Olfactory training was performed over a period of 12 weeks. Patients exposed themselves twice daily to four intense odors (phenyl ethyl alcohol: rose, eucalyptol: eucalyptus, citronellal: lemon, and eugenol: cloves). Olfactory testing was performed before and after training using the “Sniffin' Sticks” (thresholds for phenyl ethyl alcohol, tests for odor discrimination and odor identification) in addition to threshold tests for the odors used in the training process.

Results:
Compared to baseline, training patients experienced an increase in their olfactory function, which was observed for the Sniffin' Sticks test score and for thresholds for the odors used in the training process. In contrast, olfactory function was unchanged in patients who did not perform olfactory training. The present results indicate that the structured, short-term exposure to selected odors may increase olfactory sensitivity. Laryngoscope, 119:496–499, 2009

Karo Rissom

Papers

Effects of olfactory training in patients with olfactory loss