The neuromotor symptoms of Parkinson’s Disease — tremors, rigidity, slowness of movement, and difficulty with walking — are well known. But many Parkinson’s patients also suffer from a related medical condition: a severe skin rash called seborrheic dermatitis.

Now a current study by the Colorado Department of Health is investigating whether medical cannabis can ease these symptoms. While the compounds in cannabis have been anecdotally shown to help relieve the pain of skin conditions such as eczema and psoriasis, there has not previously been a controlled, randomized double-blind study to contribute evidence-based knowledge. Researchers from the University of Colorado School of Medicine were able to overcome regulatory hurdles and get clinical trials up and running.

A distinguishing characteristic of this study is that it uses transdermal patches as the delivery system for effective dosing of cannabinoids. Unlike smoking, inhalation and edibles, patches deliver cannabinoid compounds directly to the irritated skin, where they are absorbed into the epidermis and enter the bloodstream. The patches used are time-release; designed to steadily release the compounds over a 12 to 72-hour period rather than all at once.

Another reason the study uses transdermal patches is their improved bioavailability. When cannabis is either smoked or ingested, the body’s own metabolism via the respiratory or gastrointestinal systems lessens its effect before the compound have a chance to circulate through the bloodstream. Direct skin application is thus more efficient, and this is why topical creams and lotions containing CBD have become popular over-the-counter treatments for more common conditions.

A previous Colorado study took a first step at investigating whether cannabinoids help the tremors of patients living with Parkinson’s disease, but the initial findings were inconclusive. While the data suggested that cannabinoid eases symptoms, it did not show a consistent beneficial effect on motor symptoms. Future analyses will also clarify the combination of CBD and other compounds versus CBD alone; the trial participants are proponents of having as many tools at their disposal as possible to improve living with Parkinson’s.

Similarly, future skin condition studies will determine if transdermal patches are most effective on their own, or as the primary aid along with other cannabis products. A patch could be the vehicle to reduce general discomfort, while being supplemented with tinctures and/or lotions — or even edibles or vaping — for acute pain in specific areas. The most recent findings, “Cannabidiol and Cannabinoid Compounds as Potential Strategies for Treating Parkinson’s Disease and L-DOPA-Induced Dyskinesia” can be found in the journal Neurotoxicity Research.