In an experimental mouse model of Eczema endocannabinoids AEA and PEA were increased and TRPV1 and PPARα were upregulated (Petrosino et al., 2010). PEA enhances AEA activity at CB1, CB2 and TRPV1 receptors and protects against keratinocyte inflammation in a TRPV1-, but not CB1, CB2 or PPARα-dependent way.
In another mouse study, experimental dermatitis increased 2AG levels and suppressed inflammation via CB2 receptors (Oka et al., 2006).
In mice CB1 and CB2 suppressed inflammation in allergic contact dermatitis (Karsak et al., 2007).
Interstingly, topical application of THC also suppresses skin inflammation, but in a CB1- and CB2-independent way (Gaffal et al., 2013).
A comparative study into the topical anti-inflammatory activity of cannabinoids (on croton oil-inflamed skin in mice) showed that Δ8THC, Δ9THC and THCV are about half as effective in reducing inflammation as Indometacin (a commonly used Non-steroid anti-inflammatory drug), but approximately 5 times more effective than CBCV and CBD. CBC and CBDV had no appreciable anti-inflammatory activity (Tubaro et al., 2010).
Gaffal, E., Cron, M., Glodde, N., and Tüting, T. (2013). Anti-inflammatory activity of topical THC in DNFB-mediated mouse allergic contact dermatitis independent of CB1 and CB2 receptors. Allergy 68, 994–1000.
Karsak, M., Gaffal, E., Date, R., Wang-Eckhardt, L., Rehnelt, J., Petrosino, S., Starowicz, K., Steuder, R., Schlicker, E., Cravatt, B., et al. (2007). Attenuation of allergic contact dermatitis through the endocannabinoid system. Science 316, 1494–1497.
Oka, S., Wakui, J., Ikeda, S., Yanagimoto, S., Kishimoto, S., Gokoh, M., Nasui, M., and Sugiura, T. (2006). Involvement of the cannabinoid CB2 receptor and its endogenous ligand 2-arachidonoylglycerol in oxazolone-induced contact dermatitis in mice. J. Immunol. Baltim. Md 1950 177, 8796–8805.
Petrosino, S., Cristino, L., Karsak, M., Gaffal, E., Ueda, N., Tüting, T., Bisogno, T., De Filippis, D., D’Amico, A., Saturnino, C., et al. (2010). Protective role of palmitoylethanolamide in contact allergic dermatitis. Allergy 65, 698–711.
Tubaro, A., Giangaspero, A., Sosa, S., Negri, R., Grassi, G., Casano, S., Della Loggia, R., and Appendino, G. (2010). Comparative topical anti-inflammatory activity of cannabinoids and cannabivarins. Fitoterapia 81, 816–819.