Psoriasis is a chronic inflammatory disease and it is considered one of the most prevalent autoimmune (1) conditions, affecting 1.5–4% of the world's population, steadily increasing in incidence and prevalence (2). Clinically, psoriasis presents as round, erythematous, well-delimited plaques which may be covered with silvery scales, having a significant effect on quality of life in patients (3).

Psoriasis is a condition with a complex ethiopathogenesis (4), classically managed with immunosuppressive therapy and biologic agents. These therapies, however effective, are plagued by long-term adverse effects (5) impacting long-term treatment (6,7), decreasing compliance and increasing self-medication (8).

Complementary and alternative medicine (CAM) is a popular option in self-medicating patients suffering from psoriasis, with 30–40% of patients using or having used these remedies in combination with conventional psoriasis therapy (9). However, the lack of standardization and research on the safety profiles and effects of these products leaves CAM classed as ‘anecdotal evidence’ among dermatologists (5). With these products increasing in popularity, further research is needed to clarify their effects and, hopefully, provide new options to patients suffering from psoriasis.

The purpose of our study was to analyze the effects of the sea buckthorn extract on patients diagnosed with psoriasis. Pending analysis of its content, sea buckthorn was found to contain more than 190 compounds, including vitamins, fatty acids, amino acids, phenols, terpenes and tannins (10,11). This analysis, combined with anecdotal evidence from traditional medicine, makes sea buckthorn extract a valid candidate for our research.

The results of our study show that the use of sea buckthorn extract was correlated with an improved PASI in treated lesions, compared to the baseline (initial evaluation), 4-week mark and while compared to placebo. The placebo group noted a worsening of the psoriasis lesions during the 8-week trial. The overall PASI score did not vary, as it was influenced by both the improved, treated side as well as the worsened, placebo-treated lesions. The DLQI score showed an improvement over the 8-week treatment. This enables us to report that the sea buckthorn extract proved useful in the treatment of psoriasis lesions in our experimental group.

Sea buckthorn is traditionally considered a panacea, with reported anti-atherogenic, hypoglycemic, anti-aggregant, antioxidant, antibacterial, anti-ulcer, anti-inflammatory, antihypertensive and anticancer properties. Studies have described beneficial effects of sea buckthorn in hepatic disease, wound healing (12), atopic dermatitis and radiation protection (10,11,13). However, we did not identify studies exploring the efficacy of this extract when applied topically to psoriasis lesions.

Our study was conducted on newly-diagnosed patients, which ensured that the obtained progress was a result of our experimental therapy, not of previous treatment. All patients were diagnosed with mild to moderate psoriasis; patients with severe forms of psoriasis were excluded, as to minimize the interference of other systemic therapies with the results of the sea buckthorn preparation (14–16). All 10 patients completed the 8 weeks of therapy and follow-up successfully, suggesting that this form of herbal therapy is well accepted and tolerated by patients on a subjective level.

While offering conclusive results, our study does present a series of limitations. The sample size taken into consideration was small (10 subjects), with follow-up being relatively short: eight weeks. Furthermore, considering the small PASI scores, the obtained results may be amplified in their effect: For instance, for a PASI of 2, an increase to 3 reflects as a 50% worsening, whereas in larger PASI scores, 1 point of difference will reflect in a less powerful manner.

Another source of bias resides in the study design due to logistical reasons, only a single-blind study design was feasible at this point, which introduces the concern of observer bias towards the lesions.

One strong aspect of the study lies in the formulations used; the sea buckthorn oily extract is orange in color, and has a distinctive scent. To camouflage this, we suspended the oily extract in corn oil, a very pungent, bright orange oil. The placebo preparation was pure corn oil, and undistinguishable from the sea buckthorn oil.

As such, our results constitute a preliminary, encouraging finding on the subject of CAM in psoriasis. Studies on larger groups of subjects, with more elaborate measurements and spanning longer time intervals would be useful in confirming our findings, potentially leading to the consecration of sea buckthorn as either a primary treatment in psoriasis, or an adjuvant in combination with conventional medication.

Exploring the effect of sea buckthorn on psoriasis lesions may benefit from more techniques which have proven themselves as valuable tools for skin monitoring, such as dermoscopy or in vivo reflectance confocal microscopy (17,18). Furthermore, applying other scores such as PGA alongside PASI and DLQI would improve the accuracy of the study.

The results of our study offer the base incentive for further studying this extract, which could offer affordable, low-adverse-effects and accessible therapies for the increasingly stringent problem of psoriasis.