“Medical marijuana is becoming widely available to patients in the U.S. and with recreational marijuana now legalized in many states, patient interest is on the rise.
The endocannabinoid system plays an important role in skin homeostasis in addition to broader effects on neurogenic responses such as pruritus and nociception, inflammation, and immune reactions. There are numerous studies of in vitro and animal models that provide insight into the possible mechanisms of cannabinoid modulation on pruritus, with the most evidence behind neuronal modulation of both peripheral itch fibers and centrally-acting cannabinoid receptors.
In addition, human studies, while limited due to differences in cannabinoids used, disease models, and delivery method, have consistently shown significant reductions in both scratching and symptomatology in chronic pruritus. Clinical studies that have shown reduction in pruritus in several dermatologic (atopic dermatitis, psoriasis, asteatotic eczema, prurigo nodularis, allergic contact dermatitis) and systemic (uremic pruritus, cholestatic pruritus) diseases.
These preliminary human studies warrant controlled trials to confirm the benefit of cannabinoids for treatment of pruritus and to standardize treatment regimens and indications. In patients who have refractory chronic pruritus after standard therapies, cannabinoid formulations may be considered as an adjuvant therapy where it is legal.”
“Cannabis is increasingly being used world-wide to treat a variety of dermatological conditions. Medicinal cannabis is currently legalized in Canada, 31 states in America and 19 countries in Europe. The authors reviewed the literature on the pharmacology and use of 
“Endocannabinoids (ECs) are important regulators of cell signaling.
“The present study investigates the potential effect of a Cannabis sativa L. ethanolic extract standardized in cannabidiol as antiinflammatory agent in the skin. The extract inhibited the release of mediators of inflammation involved in wound healing and inflammatory processes occurring in the skin. Cannabis extract and cannabidiol showed different effects on the release of interleukin-8 and vascular endothelial growth factor, which are both mediators whose genes are dependent on NF-κB. Our findings provide new insights into the potential effect of Cannabis extracts against inflammation-based skin diseases.” 
