The use of cannabis and cannabinoids to treat disorders of the skin is nothing new, and was first referenced in the annals of scientific literature more than a century ago. Dr Henry Granger Piffard, who founded the prestigious journal JAMA Dermatology, wrote in an early textbook that “a pill of cannabis indica at bedtime has at my hands sometimes afforded relief to the intolerable itching of eczema.” Since then, a number of studies have provided further evidence for the efficacy of cannabinoids at treating the skin.
Cannabinoids And The Skin
The fact that cannabinoid receptors are found in the skin of both mice and humans implies that they must play a significant role in the regulation of mammalian skin functions. Confirmation of this theory came when researchers noted that mice that were genetically manufactured to lack these receptors suffered from an increase in allergies and skin rashes[i].
This is important as many skin conditions – such as eczema and psoriasis – are characterised by inflammation resulting from a faulty immune response among skin cells. Fortunately, cannabinoids have been found to help re-balance the immune activity of skin cells, while also regulating barrier formation and homeostasis.
Certain cannabinoids also have anti-microbial properties, with cannabidiol (CBD) being extremely effective at repelling a bacteria called Staphylococcus aureus, which often triggers flare-ups in eczema sufferers. Interestingly, CBD also downregulates a gene called NRIP1, which tends to be overexpressed in the skin cells of people with psoriasis.
As if that weren’t impressive enough, cannabinoids that bind to the CB1 receptor have also been shown to kill skin cancer cells in a petri dish[ii].
Treating The Skin With Cannabinoids
Clinical trials are currently underway with the aim of proving the efficacy of cannabinoids at healing skin condition. Within the context eczema and psoriasis, such treatments could turn out to be a game-changer, as these disorders currently have no cure and sufferers are often forced to take potentially harmful steroids and immunoregulators in order to control their symptoms.
One synthetic cannabinoid called Palmitoylethanolamide (PEA) has already been approved by the FDA for the treatment of eczema, after a study revealed that it brought about an 80 percent decrease in symptom severity. It’s worth noting that PEA binds to a receptor called GPR55, which is also a target receptor for CBD, suggesting that the latter may also be effective for the treatment of certain skin disorders[iii].
This theory was recently put to the test in a study in which people with eczema and psoriasis were given CBD to apply topically twice a day for three months. Results indicated that symptoms were “significantly improved” in every patient, with no negative side effects reported[iv].
Preclinical studies have also shed light on the role of cannabinoids in wound healing and barrier formation following skin lesions. Mice that had suffered a skin injury were found to recover faster if treated topically with an endocannabinoid called anandamide, which, like THC, binds to the CB1 receptor. In contrast, the recovery of damaged skin cells was delayed in mice that had been bred to lack this receptor, further highlighting the important role that cannabinoids play in regulating skin function[v].
[i] Bíró T, Tóth BI, Haskó G, Paus R, Pacher P. The endocannabinoid system of the skin in health and disease: novel perspectives and therapeutic opportunities. Trends in pharmacological sciences. 2009 Aug 1;30(8):411-20. – https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2757311/
[ii] Tóth KF, Ádám D, Bíró T, Oláh A. Cannabinoid Signaling in the Skin: Therapeutic Potential of the “C (ut) annabinoid” System. Molecules. 2019 Jan;24(5):918. – https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6429381/
[iii] Pulvirenti N, Nasca MR, Micali G. Topical adelmidrol 2% emulsion, a novel aliamide, in the treatment of mild atopic dermatitis in pediatric subjects: a pilot study. Acta Dermatovenerologica Croatica. 2007 Feb 1;15(2):0-. –
[iv] Palmieri B, Laurino C, Vadalà M. A therapeutic effect of cbd-enriched ointment in inflammatory skin diseases and cutaneous scars. Clin Ter. 2019 Mar 1;170(2):e93-9. – https://pubmed.ncbi.nlm.nih.gov/30993303/
[v] Kim HJ, Kim B, Park BM, Jeon JE, Lee SH, Mann S, Ahn SK, Hong SP, Jeong SK. Topical cannabinoid receptor 1 agonist attenuates the cutaneous inflammatory responses in oxazolone‐induced atopic dermatitis model. International journal of dermatology. 2015 Oct;54(10):e401-8. – https://pubmed.ncbi.nlm.nih.gov/26095080/