Psoriasis and CBD: skin, immunity and endocannabinoid signaling

Psoriasis is more than a skin problem

Red plaques, scaling, itching and sometimes fissures are the visible manifestations of psoriasis. Behind them is an immune-mediated inflammatory disorder involving both immune cells and keratinocytes, the main cells of the epidermis. Psoriasis is not simply “skin growing too fast”; immune signals and altered skin-cell maturation sustain each other.

Keratinocytes and the IL-23–Th17–IL-17 pathway

Keratinocytes normally develop in deeper layers and gradually move outward. In psoriasis they multiply and mature abnormally, creating characteristic scales. An important inflammatory pathway involves IL-23, Th17 cells and IL-17. IL-17 stimulates keratinocytes, which in turn release substances that recruit immune cells and perpetuate inflammation. This pathway also helps explain why established biologic medicines targeting IL-17 or IL-23 can be effective for many patients.

The skin has endocannabinoid signaling of its own

Skin contains CB1 and CB2 receptors, the endocannabinoids anandamide and 2-AG, and related signaling components such as TRPV1 and PPAR receptors. These systems are studied in relation to proliferation, differentiation, sebum production, itch, pain and local immunity. The presence of these components makes cannabinoid research scientifically reasonable; it is not itself proof of a useful treatment.

CBD and epidermal cells: promising laboratory observations

Cell experiments suggest that CBD and other cannabinoids can influence keratinocyte proliferation. Some laboratory models reported inhibition of excessive proliferation with THC, CBG or CBN as well. Several findings involve pathways beyond CB1 and CB2, including PPARγ. Effects in isolated cells, however, do not tell us whether a lotion will improve psoriasis in a person.

Could cannabinoids modify immune inflammation?

CB2 is involved in signaling by several immune-cell populations. In certain animal models resembling psoriasis, lack of CB2 was associated with greater inflammation and increased inflammatory mediators such as TNF, IL-1β and IL-17; CB2 stimulation changed parts of that response. This suggests two research targets: keratinocytes and immune cells. Neither animal data nor plausible mechanisms establishes clinical benefit.

What do clinical studies show?

Small early studies of topical cannabinoid preparations reported improvements in some skin or itch measurements. A split-body design—treating one side of the same person and comparing it with a control—also generated an encouraging signal. A later randomized, double-blind trial enrolled 28 participants and tested oral CBD oil against placebo. It did not show a statistically significant improvement in the Psoriasis Area and Severity Index (PASI). The preparation was generally well tolerated, and temporary changes in itch and time taken to fall asleep were reported, but these did not establish sustained disease control. This oral trial should be distinguished from the earlier topical studies.

Itching may be a more realistic target than clearing lesions

A dermatology review combining quantitative outcomes found a modest signal for relief of itch, while advantages for other skin outcomes were not consistent. Chronic itching matters: scratching may damage the skin, disturb sleep and intensify inflammation. Nevertheless, a product that eases itching has not necessarily changed the immunologic activity of psoriasis.

A skin cream is not equivalent to an oral product

Topical delivery might theoretically limit systemic exposure, but cannabinoids are highly lipophilic. The base of a cream, its concentration and its delivery technology can determine how much active substance penetrates to the relevant tissue. Two products labelled “CBD cream” are therefore not interchangeable. Research on one formulation cannot automatically be generalized to others.

Can CBD replace biologic psoriasis treatment?

Not on the evidence reviewed here. Established psoriasis therapies, including biologics targeting immune pathways, have been tested in substantially larger controlled studies. The cannabinoid literature remains comparatively small and mixed. Do not discontinue prescribed therapy on the basis of experimental or early topical studies.

What we can conclude

The skin's endocannabinoid system is a legitimate research target. Laboratory work and animal studies provide hypotheses about epidermal and immune effects, but the clinical evidence does not currently establish CBD as a treatment that reliably reduces psoriasis severity. Symptom relief—particularly itch—may warrant further study, with careful attention to formulation, safety and rigorous trials.

Read original Hebrew article ↗

Scientific sources cited by the Hebrew original

1. Cannabis and cannabinoids in dermatology: a systematic review and meta-analysis of quantitative outcomes. Read source ↗
2. The Perspective of Cannabidiol in Psoriasis Therapy. 2024. Read source ↗
3. Cannabinoids for the treatment of autoimmune and inflammatory skin diseases: A systematic review. Read source ↗
4. Efficacy and safety of cannabidiol oil in psoriasis: a randomized, double-blind, placebo-controlled trial. Read source ↗