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Overview of Psoriasis

Psoriasis is a relatively common autoimmune skin disorder that causes cells to build up on the surface of the skin, leading to thick, red skin with silvery scales. Patches can show up anywhere on the body, but most commonly develop on the elbows, knees, back, face and scalp, palms and feet.

Psoriasis is caused by a problem with the body’s immune system. Cell turnover is a normal process where skin cells growing deep in the skin rise to the surface. Typically, this process takes a month, but in someone with psoriasis, the process takes just days, as the cells rise to the skin’s surface too quickly. The condition most commonly occurs in adults.

The appearance of psoriasis patches can vary between individuals. Some may experience red patches of skin with silvery scales, while others may develop dry, cracked skin that bleeds. The patches can be itchy and painful. The severity of the psoriasis symptoms often fluctuates, with flare-ups lasting weeks or months at a time. Infections, stress, dry skin and certain medicines can make symptoms worse.

Psoriasis is likely caused by a type of white blood cells that mistakenly attack healthy skin cells. These overactive T cells also trigger additional immune responses, causing blood vessels in the skin to dilate. Genetics may play a role, but environmental factors such as infections, skin injuries, stress, cold weather, smoking, heavy alcohol consumption and certain medications may trigger psoriasis.

Psoriasis may also cause swollen and stiff joints and thickened or ridged nails in a condition called psoriatic arthritis. It occurs when the body’s immune system begins to attack healthy cells and tissue, leading to joint inflammation and skin cell overproduction. Joints throughout the entire body can be affected, including the spine and fingers. The signs and symptoms can resemble those of rheumatoid arthritis. The condition can also cause pain in the feet and lower back, and swollen fingers and toes.

While psoriasis cannot be cured, certain treatments can slow how quickly skin cells grow and offer relief. Medications such as topical corticosteroids, vitamin D analogues, anthralin, topical retinoids, calcineurin inhibitors and salicylic acid can help manage inflammation, reduce scaling and encourage dead skin cell sloughing. Additionally, moisturizers and sunlight exposure can also help improve psoriasis symptoms.

Findings: Effects of Cannabis on Psoriasis

Studies indicate that the cannabinoids found within cannabis can help manage psoriasis through their interaction with the endocannabinoid system. When the endocannabinoid system is disrupted, it can lead to the development of autoimmune diseases like psoriasis. However, studies show that cannabinoids’ interaction with cannabinoid receptors within the endocannabinoid system (ECS) help regulate proper function of the immune system2,5,12. Earlier clinical trial data found that cannabis helps prevent psoriasis flare-ups by activating the cannabinoid 2 (CB2) receptors of the ECS4. Most recently, a literature review concluded that cannabinoids’ anti-inflammatory effects and their regulating affects on the immune system make them a potential treatment agent for psoriasis3.

Research also suggests that cannabis can help treat psoriasis symptoms by managing the over activity of T cells. One study found that cannabinoid’s interaction with cannabis receptors of the body’s ECS is implicated in several biological processes related to the skin, including proliferation of skin cells1. A later study determined that CB receptors likely play a circumstantial role in T cell activity, but that cannabis’ ability to inhibit the activity of the cells is unrelated to its activation of CB receptors13. Four of the major cannabinoids found within cannabis, including tetrahydrocannabinol (THC), cannabidiol (CBD), cannabinol (CBN) and cannabigerol (CBG), have been shown to effectively inhibit overactive T cells and thereby play a therapeutic role in psoriasis treatment efforts13.

Cannabinoids’ anti-inflammatory properties have also been associated to their application for the treatment of psoriasis7. Additionally, studies have found that through the activation of CB2 receptors, cannabinoids can help alleviate, and in some cases reverse, skin inflammation damage6.


  1. Bíró, T., Tóth, B. I., Haskó, G., Paus, R., and Pacher, P. (2009). The endocannabinoid system of the skin in health and disease: novel perspectives and therapeutic opportunities. Trends in Pharmacological Sciences, 30(8), 411–420. Retrieved from

  2. Croxford, J.L., and Yamamura, T. (2005, September). Cannabinoids and the immune system: potential for the treatment of inflammatory diseases? Journal of Neuroimmunology, 166(1-2), 3-18. Retrieved from

  3. Derakhshan, N., and Kazema, M. (2016, May 11). Cannabis for refractory psoriasis-high hopes for a novel treatment and a literature review. Current Clinical Pharmacology, [Epub ahead of print]. Retrieved from

  4. Fowler, C.J. (2005, December). Pharmacological properties and therapeutic possibilities for drugs acting upon endocannabinoid receptors. Current Drug Targets: CNS and Neurological Disorders, 4(6), 685-96. Retrieved from

  5. Klein, T.W., Newton, C., Larsen, K., Lu, L., Perkins, I., Nong, L., and Friedman, H. (2003, October). The cannabinoid system and immune modulation. Journal of Leukocyte Biology, 74(4), 486-96. Retrieved from

  6. Li, S.S., Wang, L.L., Liu, M., Jiang, S.K., Zhang, M., Tian, Z.L., Wang, M., Li, J.Y., Zhao, R., and Guan, D.W. (2016). Cannabinoid CB2 receptors are involved in the regulation of fibrogenesis during skin wound repair in mice. Molecular Medicine Reports, 13(4), 3441–3450. Retrieved from

  7. Mounessa, J.S., Siegel, J.A., Dunnick, C.A., and Dellavalle, R.P. (2017, April 14). The role of cannabinoids in dermatology. Journal of the American Academy of Dermatology, pii: S0190-9622(17)30308-0. doi: 10.1016/j.jaad.2017.02.056. [Epub ahead of print]. Retrieved from

  8. Oláh, A., Tóth, B.I., Borbíró, I., Sugawara, K., Szöllõsi, A.G., Czifra, G., Pal, B., Ambrus, L., Kloepper, J., Camera, E., Ludovici, M., Picardo, M., Voeta, T., Zouboulis, C.C., Paus, R., and Bíró, T. (2014). Cannabidiol exerts sebostatic and antiinflammatory effects on human sebocytes. The Journal of Clinical Investigation, 124(9), 3713–3724. Retrieved from

  9. Psoriasis. (2015, June 17). Mayo Clinic. Retrieved from

  10. Psoriasis. (2014, June 26). MedlinePlus. Retrieved from

  11. Psoriatic arthritis. (2014, January 29). Mayo Clinic. Retrieved from

  12. Tanasescu, R., and Constantinescu, C.S. (2010, August). Cannabinoids and the immune system: An overview. Immunobiology, 215(8), 588-597. Retrieved from

  13. Wilkinson, J.D., and Williamson, E.M. (2007, February). Cannabinoids inhibit human keratinocyte proliferation through a non-CB1/CB2 mechanism and have a potential therapeutic value in the treatment of psoriasis. Journal of Dermatological Science, 45(2), 87-92. Retrieved from

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