Cannabinoids - a class of chemicals found in cannabis - may be effective as a topical treatment for an array of skin diseases, including psoriasis, severe itching, and atopic and contact dermatitis. This is the conclusion of a new review by researchers from the University of Colorado.
The team also noted a link between injection with tetrahydrocannabinol (THC) - the psychoactive compound in cannabis - and a reduction in tumor growth in mice with melanoma, the deadliest form of skin cancer.
Senior study author Dr. Robert Dellavalle, associate professor of dermatology at the University of Colorado School of Medicine, recently published their findings in the Journal of the American Academy of Dermatology.
In the United States, cannabis is becoming increasingly legalized for medicinal purposes, including for the treatment of nausea, pain, and inflammation.
A number of studies have also investigated whether the active components of cannabis - known as cannabinoids - might show promise as a treatment for skin disorders.
For their research, Dr. Dellavalle and colleagues reviewed the existing evidence surrounding this association.
Anti-inflammatory properties of cannabinoids might explain skin benefits
According to the researchers, current literature suggests that cannabis might be an effective treatment for a variety of skin disorders, particularly pruritus - a condition characterized by severe itching.
As an example, the team points to one study whereby 21 adults with pruritus applied a cannabinoid cream twice daily for 3 weeks. Eight of the adults experienced complete eradication of pruritus as a result.
Other studies suggest that cannabinoids might also be effective for the treatment of melanoma; the team cites studies that identified a decrease in tumor growth in melanoma mouse models following injection with THC.
The researchers also uncovered studies that showed that THC reduced inflammation in mice, which indicates that the skin health benefits of cannabinoids might be down to their anti-inflammatory properties.
Dr. Dellavalle warns that the majority of studies included in this review involved animal models, and large-scale clinical trials assessing the safety and efficacy of topical cannabinoids for skin diseases in humans have yet to be conducted.
However, he notes that the current evidence suggests that patients with skin diseases who fail to respond to conventional treatments might benefit from topical cannabinoid therapies.
"These diseases cause a lot of problems for people and have a direct impact on their quality of life," says Dr. Dellavalle. "The treatments are currently being bought over the Internet and we need to educate dermatologists and patients about the potential uses of them."
When it comes to melanoma, however, Dr. Dellavalle says that he does not recommend topical cannabinoids as a treatment based on current findings.