The Role of Topical Cannabinoids in the Treatment of Pruritic and Inflammatory Skin Disorders

Objective: The purpose of this paper is to assess whether current topical cannabinoid formulations offer a safe and efficacious treatment alternative to traditional topical corticosteroid therapies for patients suffering from pruritic and inflammatory skin disorders. Methods: Comprehensive literature review (PebMed, Medline, and Cochrane search engines) was conducted to compile all relevant articles known on topical cannabinoid use in inflammatory skin disorders. A comprehensive review and analysis of these compiled articles was conducted. Results: Mouse-model studies utilizing topical cannabinoid creams demonstrate reduction of cytokine-related inflammatory pathways and improved epidermal barrier function.[1] A clinical trial evaluating uremic pruritus in hemodialysis patients (n=23) demonstrated a significant reduction (p\u3c0.0001) of pruritus, as well as xerosis (p=0.0001), after using a lipid-rich cannabinoid N-palmitoylethanolamine (PEA) cream twice a day for three weeks.[2] A much larger (2,456 subjects) multicenter, observational, non-controlled, open-labelled prospective cohort study assessed quality-of-life variables in patients with mild to moderate atopic eczema.[3] Twice a day application of a PEA-containing cream showed significant relief of symptoms (itch “much improved” in 37% and “improved” in an additional 45%) and 55.7% of patients discontinued use of any concomitant steroid creams by the last week of the study (average 38 days). While in-vivo human keratinocyte studies have been conducted on skin samples from psoriatic patients,[4] no real-world clinical trials involving topical cannabinoid therapies have been published. Conclusions: Present data shows great promise for topical cannabinoid-receptor antagonists to be beneficial in the treatment algorithm and management of inflammatory skin disorders. Health care providers should be questioning patients about the use of these products because they are readily available to the public without regulation or prescription requirements. Mouse-model studies utilizing topical cannabinoid creams demonstrate reduction of cytokine-related inflammatory pathways and improved barrier function, while limited human trials demonstrate patient-reported improvement of uremic and atopic dermatitis-related pruritus. There are currently no randomized, head-to-head clinical trials that measure and critically evaluate topical steroid therapies vs topical cannabinoid treatments. Thus, the lack of proven clinical superiority, very limited safety and side-effect data, and the absence of FDA approval should prevent immediate adoption and utilization of these topical products by dermatology healthcare providers. More animal and human scientific trials are needed to determine if topical cannabinoid treatments can replace, or safely complement, topical cortisone therapies for patients suffering from inflammatory pruritic skin conditions