What does the research say about the use of cannabinoids for the treatment of itch?
Clinical Applications
Dr. Schwarzenberger is the former physician editor of DermWorld. She interviews the author of a recent study each month.
By Kathryn Schwarzenberger, MD, May 1, 2020
In this month’s Clinical Applications column, Physician Editor Kathryn Schwarzenberger, MD, talks with Mark Bechtel, MD, about his recent JAAD article ‘Cannabinoids for the treatment of chronic pruritus: A review.’
Dr. Schwarzenberger: For our readers who might have missed your recent article, can you briefly describe your research and your significant findings?
Dr. Bechtel: Our research focused on reviewing the complex nature of the endocannabinoid system (ECS), which is a broad class of endogenous and exogenous arachidonic acid-derivative compounds, and potential therapeutic benefit on skin disorders. The ECS is a lipid-signaling system, which maintains epidermal homeostasis and plays a role in inflammation. Cannabinoids are ligands to the cannabinoid receptors CB1, CB2, and the transient receptor potential (TRP) ion channels. A literature review suggests the anti-pruritic effects of cannabinoids are due to a combination of effects on neuronal activation, transmission along the afferent pathways, and local modulation of keratinocytes and mast cells.
Dr. Schwarzenberger: How did you become interested in this topic?
Dr. Bechtel: I became interested in cannabinoids as an alternative therapy for treating medical disorders because of my work on health care policy committees in Ohio. As chair of the State Medical Board of Ohio’s Marijuana Policy Committee, I help determine new qualifying medical indications for the treatment of various medical conditions, based on evidence-based medicine and expert testimony. We currently have 20 approved medical indications for prescribing medical marijuana in Ohio.
Dr. Schwarzenberger: Your article provided a wonderful discussion of the endocannabinoid system and how they might function to decrease itching. However, I suspect some of us still get confused by the difference between marijuana, CBD, and hemp. Can you explain the difference?
Dr. Bechtel: Phytocannabinoids derived from the marijuana plant, Cannabis sativa, include: Δ (9) – tetrahydrocannabinol (THC) and cannabidiol (CBD). Medical marijuana contains THC, which produces the psychoactive effects, while CBD oil does not contain THC and has no psychoactive stimulation. Hemp is a strain of the Cannabis sativa plant species, which has been used in the past for industrial purposes. Hemp oil has only traces of CBD and THC. Because it contains high quantities of omega 3 and omega 6 fatty acids, it can be used as an emollient.
Dr. Schwarzenberger: Why hasn’t there been more research in this area to date?
Dr. Bechtel: Research into medical marijuana has been severely limited due to federal and state regulations. The legal prescribing of medical marijuana varies widely from state to state. Many academic institutions have concerns about research or prescribing medical marijuana. As a result, there are very limited double-blinded, controlled clinical trials evaluating medical marijuana.
Dr. Schwarzenberger: Do you anticipate that this will become a significant part of our anti-itch armamentarium in the future? What will it take for this to happen?
Dr. Bechtel: Cannabinoids, based on their pharmacodynamics, have the potential to be a significant part of our anti-itch therapeutics. The delivery method for cannabinoids, which are highly lipophilic, determines efficacy due to different bioavailability. Topical application and oral administration of cannabinoids have shown promise in reducing pruritus in atopic dermatitis, asteatotic eczema, allergic contact dermatitis, prurigo nodularis, uremic pruritus, and cholestatic pruritus.
Mark Bechtel, MD serves as professor and division director of dermatology at The Ohio State University Wexner Medical Center. His article appeared in JAAD. Dr. Bechtel has no relevant financial or commercial conflicts of interest.
Disclaimer: The views and opinions expressed in this article do not necessarily reflect those of DW.
