Anti-inflammatory properties in a cannabis compound could help treat itching and a wide-range of other skin diseases, say, researchers.

The new study, published online in the Journal of the American Academy of Dermatology, summarises the current literature on the subject and concludes that pharmaceuticals containing cannabinoids may be effective against eczema, psoriasis, atopic and contact dermatitis.

"Perhaps the most promising role for cannabinoids is in the treatment of itch," said the study's senior author Robert Dellavalle, Associate Professor of Dermatology at the University of Colorado School of Medicine in the US. In one study, eight of 21 patients who applied a cannabinoid cream twice a day for three weeks eliminated severe itching or pruritus. The drug may have reduced the dry skin that gave rise to the itch, Dellavalle said. The primary driver in these cannabinoid treatments could be their anti-inflammatory properties, he added.

In the studies reviewed, the researchers found that THC (tetrahydrocannabinol) the active ingredient in marijuana, reduced swelling and inflammation in mice. At the same time, mice with melanoma saw significant inhibition of tumour growth when injected with THC. "These are topical cannabinoid drugs with little or no psychotropic effect that can be used for skin disease," Dellavalle said. Still, Dellavalle cautioned that most of these studies are based on laboratory models, and large-scale clinical trials have not been performed.