Pruritus or itching is a common symptom associated with many skin diseases, and is also considered as a secondary symptom of numerous serious complications like liver disease and renal failure. Unlike other skin sensations, pruritus is usually a result of CNS activities and typically goes untreated by standard medical therapies.
A review of the scientific literature revealed three clinical trials investigating the use of cannabinoids in the treatment of pruritus. Investigators from the University Of Miami Department Of Medicine, writing in the August 2002 issue of the American Journal of Gastroentrology, reported successful treatment of pruritus with 5 mg of THC in three patients with cholestatic liver disease. Subjects had failed to respond to standard medications prior to cannabinoid therapy and had lost their ability to work. Following evening cannabinoid administration, all three patients reported a decrease in pruritus and “marked improvement” in sleep and were eventually able to return to work. It was also found that the resolution of depression was also reported in two out of three subjects. “Delta-9-tetrahydrocannabinol may be an effective alternative in patients with intractable cholestatic pruritus,” investigators concluded.
In 2003, British researchers reported in the issue of the journal Inflammation Research that the peripheral administration of the synthetic cannabinoid agonist HU-211 significantly minimized experimentally-induced itch in 12 subjects.
Most recently, researchers at Wroclaw, Poland’s University of Medicine, Department of Dermatology, reported that the application of an endocannabinoid-based topical cream minimized remic pruritus and xerosis (abnormal dryness of the skin) in hemodialysis patients. Three weeks of twice-daily application of this cream “completely eliminated” pruritus in 38 percent of trial subjects and “significantly reduced” itching in others.
Some dermatology experts, in light of these encouraging preliminary results, now believe that cannabinoids and the cannabinoid system may represent “promising new avenues for managing itch more effectively.”
 Neff et al. 2002. Preliminary observation with dronabinol in patients with intractable pruritus secondary to cholestatic liver disease. American Journal of Gastroenterology 97: 2117-2119.
 Dvorak et al. 2003. Histamine induced responses are attenuated by a cannabinoid receptor agonist in human skin (PDF). Inflammation Research 25: 238-245.
 Dvorak et al. 2003. Cannabinoid agonists attenuate capsaicin-induced responses in human skin. Pain 102: 283-288.
 Szepietowski et al. 2005. Efficacy and tolerance of the cream containing structured physiological lipid endocannabinoids in the treatment of uremic pruritus: a preliminary study. Acta Dermatovenerologic Croatica (Croatia) 13: 97-103.
 Paus et al. 2006. Frontiers in pruritus research: scratching the brain for more effective itch therapy. Journal of Clinical Investigation 116: 1174-1185.