Chronic pruritus is an unpleasant sensation that results in the desire to scratch the skin. In mild cases, the condition is a nuisance. In extreme and persistent cases, the condition can result in a notable reduction in quality of life. It is oftentimes treatment resistant—something that can be especially problematic given that there are a limited number of therapeutic agents that have been approved by the Food and Drug Administration.
Such was the case with a woman whose case history was recently published in JAMA Dermatology. The authors, a team based at the John Hopkins Itch Center, report that the woman had severe pruritus and that her symptoms failed to improve even after treatment with “topical corticosteroids, phototherapy, topical capsaicin, doxepin, naltrexone, and butorphanol nasal spray.” Given the treatment resistant nature of the woman's condition and because cannabis has been reported to reduce the severity of pruritus since at least the early 20th century (see Sajous’s Analytic Cyclopedia of Practical Medicine), the authors decided to see if it could ease her symptoms.
The patient administered the cannabis in one of two forms: either as smokable cannabis with an 18% concentration of tetrahydrocannabinol (THC) or as a sublingual tincture with a 1:1 THC to cannabidiol (CBD) ratio. Shortly after the administration, the authors report, “her Worst Itch Numeric Rating Scale (WI-NRS) score improved from 10 of 10 to 4 of 10. With continued treatment with medical marijuana, the score on the WI-NRS over the preceding 24-hour period improved from 10 of 10 to 4 of 10 over 5 months, which was sustained at the 1-year follow-up, and then to 0 of 10 at the 16-month and 20-month follow-up.”
The treatment was so effective that the patient was able to discontinue her other pruritus treatments and reported a Dermatology Life Quality Index score reduction from 17 to 7 after three months of treatment, and then a further reduction to 1 at 20 months. She claimed mild sedation to be the only side effect. These findings suggest that cannabis may be extremely effective in the treating pruritus, though more studies are needed to confirm and to better understand the mechanism of action.
JAMA Dermatology has more.