“Pruritus” sounds like a scary disease that you don’t want to get, but what it really means is “itching.” We all deal with minor itches on a day-to-day basis, but excessive itching may be the result of a variety of different disorders affecting the skin and nervous system. Excessive itching can be debilitating to the point of disturbing one’s sleep or work schedule.
Pruritus is not a condition typically associated with medicinal marijuana use. However, a review of the available scientific literature comes up with some preliminary findings about the “antipruritic” (anti-itch) effect of marijuana and its compounds. It seems that this is one avenue which may provide sufferers some relief.
A 2002 study, which was published in The American Journal of Gastroenterology, was among the first to take a look at the relationship between marijuana and pruritus. The study followed 3 patients who suffered from intractable pruritus as a symptom of liver disease. Researchers looked at the effectiveness of marijuana’s most abundant psychoactive compound, THC, in alleviating the patient’s symptoms. They found that THC, in the form of marinol, resulted in a decrease in pruritus and an improvement in sleep. All 3 patients returned to work and 2 saw an improvement in their depression.
A clinical study carried out in 2003 sought to see how effective a synthetic cannabinoid known as HU210 was against a capsaicin-induced pain response in human skin. Researchers discovered that the cannabinoid was able to reduce the pain and sensitivity caused by the capsaicin. This study may not have directly studied the sensation of itching, but it nevertheless noted that topical cannabinoids were effective for alleviating irritation of human skin.
The same team of researchers expanded these findings and published another study in 2003 which sought to see how effective HU210 was against a histamine-induced itch. They discovered that the cannabinoid was able to relieve the itch, but not because it acted as an antihistamine. Rather, HU210 seemed to act on nerve fibers.
2005 once again saw researchers focusing on pruritus which results from a specific disorder. In this case, researchers looked at uremic pruritus, a condition which develops from renal failure. The study, published in Acta Dermatovenerologica Croatica, followed 21 patients for 3 weeks. Patients were administered a cream containing cannabinoids and structured physiological lipids.
By the end of the 3-week period, 8 patients were completely free of uremic pruritus altogether. Researchers concluded that it was “very probable” that the cannabinoids had played a role in improving their conditions, and noted the need for additional studies to confirm and clarify these promising findings.
Due to all of these previous findings, a 2006 review of the state of pruritus research noted that cannabinoids provided a “putative itch frontier.” The authors isolated what is known as “cannabinoid receptor 1” as having an important involvement in histamine-related itches. They also noted the anti-inflammatory properties of cannabinoids, as well as the fact that they may have an effect on the neuronal network of the skin.