Efficacy of probiotics for psoriasis: A systematic review and meta-analysis

The pathogenesis of psoriasis is thought to be linked to the adaptive immune system, and traditional treatments for psoriasis have focused on reducing the skin inflammation caused by immune hyperactivation. The ‘gut-skin axis’ is a theory that the health of the gut is linked to skin homeostasis and improving the gut microbiome can change immune responses. Therefore, it is theorized that using probiotics could improve the symptoms of psoriasis.

Here, we summarize a systematic review and meta-analysis by Wei et al.¹ published in the Journal of Cosmetic Dermatology on the efficacy of probiotics in patients with psoriasis.

Methods¹

• A search was performed in various databases up to November 10, 2023, with the search strategy: “probiotic” and "psoriasis" or “psoriasis pustulosis of palm”.
• Trials were included in the meta-analysis if the patients had a diagnosis of psoriasis and were treated with probiotic, and a control group that was treated with placebo.
• Studies were required to report Psoriasis Area and Severity Index (PASI) and /or Dermatology Life Quality Index (DLQI).

Key findings¹

• A total of 5 trials with 286 patients were included in this study. The characteristics of the included trials are shown in Table 1. All studies used PASI and DLQI to measure outcomes, apart from trial 5 which used only PASI.

Table 1. Trial characteristics*

Trial	Interventions		Probiotic strain	Duration (months)
	Probiotic	Control
1. Suriano, et al., 2023.2	Standard of care plus probiotics (n = 50)	Standard of care plus placebo (n = 53)	Lactobacillus rhamnosus	6
2. Moludi, et al., 2021.3	Probiotic (n = 25)	Maltodextrin capsule (n = 25)	Lactobacillus acidophilus, Bifidobacterium bifidum, Bifidobacterium lactis, and Bifidobacterium langum	2
3. Akbarzadeh, et al., 2022.4	Synbiotic product and hydrocortisone (n = 27)	Hydrocortisone and placebo (n = 25)	Lactobacillus strains, Bifido-bacteria strains, Streptococcus thermophilus, plus fructo-oligosaccharides	3
4. Gilli, et al., 2023.5	Probiotic (n = 18)	Placebo (n = 17)	Lactobacillus acidophilus, Bifidobacterium bifidum, Bifidobacterium lactis, and Bifidobacterium langum	2
5. Moludi, et al., 2022.6	Probiotic (n = 23)	Placebo (n = 23)	Lactobacillus rhamnosus	2
*Data from Wei, et al.1

• In general, PASI scores were significantly lower (p < 0.00001) in the probiotic group compared with the placebo group (Figure 1A).
• Overall, DLQI scores were also lower in the probiotic group compared with the placebo group (Figure 1B).

DLQI, Dermatology Life Quality Index; PASI, Psoriasis Area and Severity Index.
*Adapted from Wei, et al.¹

Key learnings

In this study, probiotic supplementation showed good efficacy in patients with psoriasis, as measured by PASI and DLQI scores. Single strain probiotics did not appear to be less efficacious than mixed strains. This analysis is limited by the small number of trials included and lacked laboratory indicators. Despite this, probiotics may be a good option as a complementary treatment for psoriasis alongside traditional maintenance therapy in helping to stabilize the disease.