BACKGROUND
Seborrheic dermatitis (SD) affects ~18.6-59% of persons with Parkinson’s disease (PD) and recent studies provide evidence that oral cannabidiol (CBD) therapy could reduce sebum production in addition to improving motor and psychiatric symptoms in PD. Therefore, oral CBD could be useful for improving symptoms of both commonly co-occurring conditions.
OBJECTIVE
This study investigates whether oral CBD therapy is associated with a decrease in SD severity in PD.
METHODS
Facial photographs were collected as a component of a randomized (1:1 CBD versus placebo), parallel, double-blind, placebo-controlled trial assessing the efficacy of short-term 2.5mg/kg/day oral sesame solution CBD-rich cannabis extract for reducing motor symptoms in PD. Reviewers analyzed the photographs independently and providing a severity ranking based on the Seborrheic Dermatitis Area and Severity Index (SEDASI) scale. Baseline demographic and disease characteristics, as well as post-treatment SEDASI averages and presence of SD, were analyzed with two-tailed T-tests and Pearson’s chi-squared tests.
RESULTS
Twenty-nine participants received placebo and 29 CBD for 16 days. SD severity was low in both groups at baseline, and there was no treatment effect. Generalized estimating equations regression analysis, when final blood level of CBD is included as an explanatory variable, revealed that CBD treatment trended toward reducing the presence of SD (P=0.0690 at the mean CBD final blood level of 49.29 ng/mL).
CONCLUSIONS
This study does not provide solid evidence that oral CBD therapy reduces the presence of SD among PD patients. While this study was sufficiently powered to detect the primary outcome (efficacy of CBD on PD motor symptoms), it was underpowered for the secondary outcomes of detecting changes in the presence and severity of SD. Larger studies including participants with increased disease severity and with longer treatment periods may better elucidate treatment effects and are needed to determine CBD true efficacy for SD severity.
CLINICALTRIAL
ClinicalTrials.gov Identifier: NCT03582137 (https://clinicaltrials.gov/ct2/show/NCT03582137)