Cannabis is a popular alternative to standard medication, especially for chronic conditions resistant to standard treatment. One such condition is psoriasis, an inflammatory autoimmune disorder affecting the skin.
Some people report improvement in their psoriasis symptoms after using CBD oil and other cannabis-based preparations, particularly those applied directly to the skin. This may be the result of the interaction between cannabis-derived cannabinoids and the body’s endocannabinoid system (ECS).
Research shows that the ECS plays an important role in skin health, and that its dysfunction could contribute to psoriasis. There haven’t been many clinical studies on cannabis treatment of psoriasis, but those that have been done were promising.
How cannabis works on psoriasis
Cannabis contains active compounds called cannabinoids, such as THC and CBD. Cannabinoids affect the body by interacting with the ECS, which is composed of endocannabinoids (cannabinoids made by the human body), cannabinoid receptors (primarily CB1 and CB2), and special enzymes that build and break down endocannabinoids.
The ECS regulates essential processes such as immunity, inflammation, mood, pain, stress, metabolism, appetite, and sleep in order to maintain a state of internal balance called homeostasis. The system is present in every part of the body, including the skin.
Research suggests the endocannabinoid system plays an essential role in skin health, particularly by regulating skin cell growth and inflammation. Dysfunction in this system may contribute to the development of psoriasis and other skin diseases.
Researchers have found that psoriasis sufferers have elevated endocannabinoid levels. People with psoriatic arthritis, which affects up to 30% of psoriasis patients, had higher levels of CB1 cannabinoid receptors, while those with regular psoriasis seem to have higher numbers of CB2 receptors.
A study of skin biopsies from psoriasis patients suggests that their skin cells differ in endocannabinoid-related gene expression (the process where cells read DNA to create proteins) from healthy cells. All of these findings imply that the endocannabinoid system is involved in psoriasis.
Combined with the known regulatory effects of the endocannabinoid system on stress, inflammation, and immune system function — all processes that play a key role in psoriasis — this evidence suggests that cannabinoid-based medicines can offer relief for the condition.
Medical studies on cannabis and psoriasis
Few studies have examined the use of cannabis and cannabinoids in psoriasis, but those that exist have yielded promising findings.
Most notably, a 2019 study human study looked at the beneficial effects of a topical ointment infused with CBD on chronic skin conditions. Twenty people (five with psoriasis, five with atopic dermatitis, and 10 with scarring from the two conditions) used the ointment daily for three months, resulting in significant improvement in their PASI index (a measure of psoriasis severity) as well as their symptoms and markers of skin health, including elasticity.
A 2007 study of isolated human skin cells reported that THC, CBD, and other cannabinoids reduced the hyper-proliferation (rapid growth) of keratinocyte skin cells, which are the main cause of psoriasis.
A 2016 study reported that cannabinoid-like compounds reduced skin inflammation in mice with dermatitis by reducing mast cell activation, an inflammatory process that also occurs in psoriasis.
There are also studies of cannabinoids in similar inflammatory skin conditions, such as atopic dermatitis and acne. In a 2013 study, researchers applied THC to the skin of mice with allergic atopic dermatitis, resulting in reduction of inflammation.
Similarly, a 2014 study of isolated skin cells found that CBD reduced inflammation and cell proliferation, two effects that are beneficial in psoriasis.
Studies also suggest that cannabinoids can help with itching, one of the symptoms of psoriasis. A 2002 clinical study reported that a THC-based medication called dronabinol suppressed itching caused by liver disease.
Cannabis may also help alleviate three other potential psychological symptoms of psoriasis: pain, depression, and anxiety. A 2015 review of 28 clinical studies finding concluded that there’s solid evidence to back the use of cannabinoids for pain.
There’s evidence that both of the major components of cannabis, CBD and THC, can improve mood and anxiety. A 2011 study found that CBD alleviated anxiety in people with social anxiety disorder, while a 2013 study reported that THC improved mood-related measures in healthy individuals, suggesting that it may be helpful for depression.
More human studies are needed to confirm that cannabis can treat psoriasis effectively, but current evidence suggests that it may help with some of its causes and symptoms.
Potential side effects of cannabis use
Cannabis does have potential side effects, which vary depending on what type of preparation you’re using. For example, standard, THC-rich cannabis can cause impaired memory and reaction time, increased heart rate, red eyes, dry mouth, sleepiness, and dizziness. It can also cause paranoia and anxiety in some people, especially at higher doses.
Meanwhile, CBD-rich cannabis preparations such as CBD oil don’t contain enough THC to cause intoxication. They may cause minor side effects such as diarrhea, low blood pressure (hypotension), dry mouth, lightheadedness, sleepiness, and changes in appetite. However, these effects have only been reported in studies using high doses of CBD (300 mg and above).
These symptoms only occur when cannabinoids are able to reach the bloodstream, as when you inhale, ingest, or apply a cannabis preparation under the tongue. Cannabinoids applied topically (to the skin) via a cream, ointment, or another method will not cause these effects, because they cannot penetrate deep enough to reach the bloodstream.
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