ABSTRACT
BACKGROUND/OBJECTIVES: In the last 10 years methylisothiazolinone (MI) emerged as a global cause of preservative-related ACD. New Zealand has liberal regulations for the MI concentration limit in cosmetic products compared to Europe and Australia. The aim of this study was to evaluate the prevalence of MI sensitisation in New Zealand, explore sources of MI exposure and make recommendations on New Zealand regulations for MI use. METHODS: This retrospective study included data from patients who underwent patch testing with MI from 2008 to 2021 in a tertiary hospital dermatology clinic and a private dermatology clinic in Auckland, New Zealand. Patient baseline characteristics were recorded along with results of patch testing. Sources of MI exposure were identified from medical records. RESULTS: Over the study period, 1049 patch tests were performed in 1044 patients. MI was only tested as a stand-alone allergen from 2015; positive reactions to MI increased from 5.3% in 2015 to a peak of 11.9% in 2017 and then decreased to 6.4% in 2021. The most common source of MI exposure was shampoo or conditioner (27.7% of all relevant reactions) followed by occupational exposures to paints, biocides or glue (19.1%). CONCLUSION: Both sensitisation and ACD to MI appear to be decreasing, likely secondary to changes in product compounding due to stricter concentration limits internationally. We recommend New Zealand adopt lower MI concentration limits for cosmetics to match the limits of Australia and Europe.
ABSTRACT
BACKGROUND: The potential link between isotretinoin and sexual dysfunction has been reported in various studies. However, such an association has not been explored within the context of a literature review until now. OBJECTIVES: To evaluate the methodology and quality of studies investigating this association, and to examine the definitions of sexual dysfunction used. METHODS: A scoping review approach was used to identify peer-reviewed research articles. The search terms used were: "isotretinoin", "sexual dysfunction", "erectile dysfunction", "ejaculatory disorders" "decreased libido", "female sexual interest", "female arousal disorder", "libido", "pelvic pain", "dyspareunia", "orgasmic disorder", "impotence", "ovaries", "fertility" and "menstrual irregularity". RESULTS: 54 peer-reviewed manuscripts consisting of 8 animal studies and 46 human studies consisting of 2,420 patients were included. Of the studies in humans, there were 18 case reports/case series, 2 case-controls, 4 cross-sectional studies, 6 longitudinal studies, 3 pharmacovigilance reports and 13 cohort studies. The most frequently observed dose range of isotretinoin was 0.5-1.0mg/kg/day usually for a duration of 1-6 months. More than half of the studies (54%, n=25) reported a beneficial or neutral effect of isotretinoin on sexual function. The majority of studies (89%, n = 41) were categorized as Oxford evidenced-based-medicine level 4. CONCLUSIONS: This scoping review revealed very weak evidence supporting a link between isotretinoin and sexual dysfunction. Notably, the diverse definitions of sexual dysfunction pose a significant challenge for comparative analysis. The authors advocate for a standardized definition of sexual dysfunction and a framework for determining causality in order to contribute to a more comprehensive understanding of the relationship between isotretinoin and sexual dysfunction.
