Effects of isotretinoin on the olfactory function in patients with acne

Prevalence and factors associated with olfactory impairment among patients with acne treated with oral isotretinoin: a cross-sectional study

OBJECTIVE

This study aimed to investigate the prevalence and factors associated with olfactory dysfunction in individuals exposed to Isotretinoin (ISO) for the treatment of acne, using the University of Pennsylvania Smell Identification Test (UPSIT®).

METHODS

This cross-sectional study enrolled age and sex-matched patients with acne who were current users of oral ISO and unexposed controls without olfactory complaints. UPSIT® and a validated questionnaire (Nasal Obstruction Symptom Evaluation) were administered to evaluate nasal obstruction in patients exposed to ISO.

RESULTS

A total of seventy patients were recruited, with 35 in the exposed group and 35 in the unexposed group, consisting of 18 males and 17 females in each group, aged from 17 to 47 years. The prevalence of olfactory dysfunction was higher in the exposed group compared to the non-exposed group (62.9% vs. 17.1%), yielding a Prevalence Ratio (PR) of 3.7 (95% CI 1.9-7.1). However, no participants were categorized as anosmia or severe hyposmia and the majority of dysfunction was mild hyposmia compared to moderate hyposmia (51.5% vs. 11.4%). Among the exposed individuals, gasoline, orange, coffee, and wood exhibited the highest rates of identification errors (≥54%). Olfactory function demonstrated a negative correlation with treatment duration (p = 0.01), cumulative dose (p = 0.02), and nasal obstruction (p = 0.02).

CONCLUSIONS

Olfactory dysfunction was more prevalent among ISO users, despite the patients being unaware of the disorder. Olfactory changes were correlated with treatment duration, cumulative dose, and nasal obstruction.

LEVEL OF EVIDENCE

Level 4.

A Pilot Study of Short-Course Oral Vitamin A and Aerosolised Diffuser Olfactory Training for the Treatment of Smell Loss in Long COVID

Background: Olfactory dysfunction (OD) is a common neurosensory manifestation in long COVID. An effective and safe treatment against COVID-19-related OD is needed. Methods: This pilot trial recruited long COVID patients with persistent OD. Participants were randomly assigned to receive short-course (14 days) oral vitamin A (VitA; 25,000 IU per day) and aerosolised diffuser olfactory training (OT) thrice daily (combination), OT alone (standard care), or observation (control) for 4 weeks. The primary outcome was differences in olfactory function by butanol threshold tests (BTT) between baseline and end-of-treatment. Secondary outcomes included smell identification tests (SIT), structural MRI brain, and serial seed-based functional connectivity (FC) analyses in the olfactory cortical network by resting-state functional MRI (rs-fMRI). Results: A total of 24 participants were randomly assigned to receive either combination treatment (n = 10), standard care (n = 9), or control (n = 5). Median OD duration was 157 days (IQR 127-175). Mean baseline BTT score was 2.3 (SD 1.1). At end-of-treatment, mean BTT scores were significantly higher for the combination group than control (p < 0.001, MD = 4.4, 95% CI 1.7 to 7.2) and standard care (p = 0.009) groups. Interval SIT scores increased significantly (p = 0.009) in the combination group. rs-fMRI showed significantly higher FC in the combination group when compared to other groups. At end-of-treatment, positive correlations were found in the increased FC at left inferior frontal gyrus and clinically significant improvements in measured BTT (r = 0.858, p < 0.001) and SIT (r = 0.548, p = 0.042) scores for the combination group. Conclusions: Short-course oral VitA and aerosolised diffuser OT was effective as a combination treatment for persistent OD in long COVID.

Olfactory Function and Olfactory Disorders

The sense of smell is important. This became especially clear to patients with infection-related olfactory loss during the SARS-CoV-2 pandemic. We react, for example, to the body odors of other humans. The sense of smell warns us of danger, and it allows us to perceive flavors when eating and drinking. In essence, this means quality of life. Therefore, anosmia must be taken seriously. Although olfactory receptor neurons are characterized by regenerative capacity, anosmia is relatively common with about 5 % of anosmic people in the general population. Olfactory disorders are classified according to their causes (e. g., infections of the upper respiratory tract, traumatic brain injury, chronic rhinosinusitis, age) with the resulting different therapeutic options and prognoses. Thorough history taking is therefore important. A wide variety of tools are available for diagnosis, ranging from short screening tests and detailed multidimensional test procedures to electrophysiological and imaging methods. Thus, quantitative olfactory disorders are easily assessable and traceable. For qualitative olfactory disorders such as parosmia, however, no objectifying diagnostic procedures are currently available. Therapeutic options for olfactory disorders are limited. Nevertheless, there are effective options consisting of olfactory training as well as various additive drug therapies. The consultation and the competent discussion with the patients are of major importance.

International consensus statement on allergy and rhinology: Olfaction

BACKGROUND

The literature regarding clinical olfaction, olfactory loss, and olfactory dysfunction has expanded rapidly over the past two decades, with an exponential rise in the past year. There is substantial variability in the quality of this literature and a need to consolidate and critically review the evidence. It is with that aim that we have gathered experts from around the world to produce this International Consensus on Allergy and Rhinology: Olfaction (ICAR:O).

METHODS

Using previously described methodology, specific topics were developed relating to olfaction. Each topic was assigned a literature review, evidence-based review, or evidence-based review with recommendations format as dictated by available evidence and scope within the ICAR:O document. Following iterative reviews of each topic, the ICAR:O document was integrated and reviewed by all authors for final consensus.

RESULTS

The ICAR:O document reviews nearly 100 separate topics within the realm of olfaction, including diagnosis, epidemiology, disease burden, diagnosis, testing, etiology, treatment, and associated pathologies.

CONCLUSION

This critical review of the existing clinical olfaction literature provides much needed insight and clarity into the evaluation, diagnosis, and treatment of patients with olfactory dysfunction, while also clearly delineating gaps in our knowledge and evidence base that we should investigate further.

Oral isotretinoin treatment in patients with acne vulgaris during the COVID-19 pandemic: A retrospective cohort study in a tertiary care hospital

Background

Patients with acne vulgaris continue to present increasingly in dermatology outpatient clinics and seek treatment during the COVID‐19 pandemic. As far as we know, the effect of isotretinoin on COVID‐19 has not been studied before.

Aim

We aimed to evaluate whether patients receiving oral isotretinoin are at increased risk of COVID‐19 infection by comparing them with patients on topical treatment for acne vulgaris.

Methods

The data were collected retrospectively from a cohort of 267 acne vulgaris patients, who were under follow‐up for acne vulgaris treatment during the pandemic period.

Results

Total of 227 patients (141 receiving isotretinoin treatment and 86 receiving topical treatment) were included of whom 29 patients had COVID‐19 infection during acne vulgaris treatment. Fifteen (10.6%) patients were receiving oral isotretinoin and 14 (16.3%) were receiving topical acne treatment at the time of COVID‐19 infection. The mean cumulative dose was 2340 ± 1988 mg at the time of COVID‐19 infection. The mean elapsed time between the onset of isotretinoin treatment and positive PCR result for COVID‐19 was 13.3 ± 10.3 weeks. Nine patients (64.3%) receiving isotretinoin treatment and 9 patients (60%) under topical treatment had loss of taste and smell during COVID‐19 infection. Isotretinoin treatment was not found to be associated with a significant increased risk of getting COVID‐19 (odds ratio, 0.671; 95% confidence interval, 0.247–1.823; P  = 0.434).

Conclusion

As a conclusion, the results of this study encourage dermatologists and acne vulgaris patients to initiate oral isotretinoin treatment safely during the pandemic period.