Marijuana may be useful in treating symptoms related to skin diseases including eczema and psoriasis, according to research.

The plant Cannabis sativa is known for the psychoactive THC agent found in it - which causes an intoxicating effect.

However, as states across America legalise or decriminalise marijuana, doctors and patients are showing an increased interest in the health benefits of the plant which stem from the parts of the plant that don’t cause intoxicating effects.

For marijuana to be used topically and as a potential treatment for health-related issues, researchers are focusing on the four other agents, or cannabinoids, found in the plant - cannabidiol (CBD), cannabichromene (CBC), cannabigerol (CBG), and cannabinol (CBN).

These agents don’t make the user “high,” but they can cause relief from various medical conditions, including atopic dermatitis or eczema.

Eczema is a condition that causes the skin to become itchy, red, dry, and cracked. In the UK, it affects an estimated 15 million people, according to AllergyUK.

There are numerous treatments for eczema, however, there is currently no cure.

But, according to the National Eczema Association (NEA): “It has long been observed that cannabinoids possess anti-inflammatory, antimicrobial and anti-itch qualities” with research dating back to the first textbook of dermatology referencing a use for cannabis in treating skin conditions.

In this first text, Dr Henry Granger Piffard, one of the founders of American dermatology, noted: “A pill of cannabis indica at bedtime has at my hands sometimes afforded relief to the intolerable itching of eczema.”

This relief is partly due to the powerful anti-itch effect of cannabinoids, which interact with receptors in the skin - minimising the common attributes of eczema, most notably itch caused by dry skin, histamine release, and sensory nerve fibres.

In pictures: 4/20 Marijuana world rallies Show all 26 1 /26 In pictures: 4/20 Marijuana world rallies In pictures: 4/20 Marijuana world rallies A man wears a marijuana leaf mask during the annual 4/20 cannabis culture celebration at Sunset Beach in Vancouver, British Columbia AP In pictures: 4/20 Marijuana world rallies A lady smokes marijuana on Parliament Hill on 4/20 in Ottawa, Ontario Getty Images In pictures: 4/20 Marijuana world rallies James Reed smokes a joint during the Denver 420 Rally at Civic Center Park in Denver, Colorado Getty Images In pictures: 4/20 Marijuana world rallies People sign a 4/20 sign on Parliament Hill on in Ottawa, Ontario Getty Images In pictures: 4/20 Marijuana world rallies A woman smokes marijuana on Parliament Hill on 4/20 in Ottawa, Ontario. Polling released showed strong support in Canada for a government drive to legalise recreational use of marijuana, but many would like the proposed minimum age for consumption to be raised. Sixty-three percent of respondents told the Angus Reid Institute they support legalisation Getty Images In pictures: 4/20 Marijuana world rallies A man smokes marijuana during the annual 4/20 marijuana rally on Parliament Hill in Ottawa, Ontario, Canada Reuters In pictures: 4/20 Marijuana world rallies Demonstrators smoke marijuana during the '4/20 Santiago' rally in favour of legalisation in front of the La Moneda presidential palace in Santiago, as part of the Global Marijuana March which is being held in hundreds of cities worldwide Getty Images In pictures: 4/20 Marijuana world rallies People play with a mock marijuana joint during a 4/20 party to demand legalisation and to celebrate marijuana culture outside the Senate building in Mexico City, Mexico Reuters In pictures: 4/20 Marijuana world rallies Adam Eidinger, co-founder of DCMJ, hands out free marijuana joints to DC residents who worked on Capitol Hill as part of the 1st Annual Joint Session to mark '4/20' day and promote legalising marijuana on Capitol Hill in Washington, DC Getty Images In pictures: 4/20 Marijuana world rallies In pictures: 4/20 Marijuana world rallies Police arrest Rachel Ramone Donlan after she handed out free marijuana joints to DC residents who worked on Capitol Hill as part of the 1st Annual Joint Session to mark '4/20' day and promote legalising marijuana on Capitol Hill in Washington, DC AFP/Getty Images In pictures: 4/20 Marijuana world rallies Police arrest Rachel Ramone Donlan after she handed out free marijuana joints to DC residents who worked on Capitol Hill as part of the 1st Annual Joint Session to mark '4/20' day and promote legalising marijuana on Capitol Hill in Washington, DC Getty Images In pictures: 4/20 Marijuana world rallies Thousands of people gather to smoke marijuana during the '420 Santiago'rally in front of the La Moneda presidential palace in Santiago Getty Images In pictures: 4/20 Marijuana world rallies People attend the Denver 420 Rally at Civic Center Park in Denver, Colorado Getty Images In pictures: 4/20 Marijuana world rallies Kevin Barron and Lasean Moore of Raleigh, North Carolina, share a joint during the Denver 420 Rally at Civic Center Park in Denver, Colorado Getty Images In pictures: 4/20 Marijuana world rallies Nic Ruhl takes a pull on a giant hand rolled joint at precisely 4:20pm MDT during the Denver 420 Rally at Civic Center Park in Denver, Colorado Getty Images In pictures: 4/20 Marijuana world rallies Various cannabis paraphernalia on display at a vendor's stall during the Denver 420 Rally at Civic Center Park in Denver, Colorado Getty Images In pictures: 4/20 Marijuana world rallies Mo Banez, of Austin, Texas, lights a joint during the Denver 420 Rally at Civic Center Park in Denver, Colorado Getty Images In pictures: 4/20 Marijuana world rallies A man displays a large container of cannabis during the Denver 420 Rally at Civic Center Park in Denver, Colorado. The rally, held annually, is a celebration of both the legalisation of cannabis and cannabis culture. Colorado is one of twenty-six U.S. states along with the District of Columbia that has legalised the use of cannabis either recreationally or medically AFP/Getty Images In pictures: 4/20 Marijuana world rallies Sitting in small groups on mats shaded by trees in the Rose Garden just across from the Knesset, participants lit up as the clock struck 4:20 for the local version of the traditional worldwide April 20 pro-marijuana events, known as '420' rallies Getty Images In pictures: 4/20 Marijuana world rallies An Israeli smokes a marijuana joint in Jerusalem during a rally at the Rose garden Getty Images In pictures: 4/20 Marijuana world rallies Sitting in small groups on mats shaded by trees in the Rose Garden just across from the Knesset, participants lit up as the clock struck 4:20 for the local version of the traditional worldwide April 20 pro-marijuana events, known as '420' rallies Getty Images In pictures: 4/20 Marijuana world rallies An Israeli girl poses with a mock marijuana joint in Jerusalem during a rally at the Rose garden, to celebrate 420 and to express their defiance of current laws Getty Images In pictures: 4/20 Marijuana world rallies aelis pass around a marijuana joint in Jerusalem during a rally at the Rose garden, to celebrate 420 and to express their defiance of current laws Getty Images In pictures: 4/20 Marijuana world rallies An Israeli smokes a marijuana joint in Jerusalem during a rally at the Rose garden, to celebrate 420 and to express their defiance of current law Getty Images In pictures: 4/20 Marijuana world rallies An Israeli smokes a marijuana joint in Jerusalem on April 20, 2017 during a rally opposite the Knesset to celebrate 420 and express defiance of current laws AFP/Getty Images

The anti-inflammatory properties of cannabinoids applied topically may also improve eczema, as can their anti-microbial effects.

According to researchers at the University of Colorado, the agent CBD is particularly helpful in curing eczema or the symptoms associated with the skin condition - and can be used as a natural alternative to commonly-used steroids.

Dr Robert Dellavalle, one of the leading researchers said: “There’s a large segment of the population that doesn’t like using steroids, even if they are topical steroids on their skin. CBD could be an alternative, natural product for them to try.

“So, when we have somebody who has tried topical steroids or topical immuno-modulators that suppress the immune system for psoriasis or eczema and they haven’t gotten completely better, there’s a potential of using this new therapy that might work in a different way and help them,” Dellavalle said.

Doctors and researchers are eager to study the health benefits of marijuana (Stock)

And the new topically-applied treatment of CBD has already been cleared by the World Health Organisation (WHO) as having no potential for abuse or harm, as multiple clinical trials have seen positive outcomes on the symptoms and appearance of skin conditions.

However, the lasting stigmas surrounding the plant and the remaining laws make it difficult for researchers to fully study the effects of the cannabinoids in marijuana.