clinical topic updates

The Role of the Microbiome in Psoriatic Disease

by Bruce E. Strober, MD, PhD


Research on the microbiome and its role in psoriatic disease continues to unfold. Our featured expert integrates emerging findings with the existing understanding of plaque psoriasis and its pathogenesis.

Expert Commentary

Bruce E. Strober, MD, PhD

Clinical Professor, Department of Dermatology
Yale University School of Medicine
New Haven, CT
Central Connecticut Dermatology
Cromwell, CT

“ . . . the theory that the microbiome acts as an environmental trigger in patients with a genetic predisposition to psoriasis is quite plausible.”

Bruce E. Strober, MD, PhD

Research connecting the gut microbiome to psoriatic disease is still in its early stages. However, if we note the importance of both genetic and environmental influences in psoriasis, the theory that the microbiome acts as an environmental trigger in patients with a genetic predisposition to psoriasis is quite plausible. Monozygotic and dizygotic twin studies have suggested that genetics accounts for only a portion of the total risk of developing psoriatic disease over a lifetime. There is very strong evidence of environmental influences, some of which may be microbial.

The cutaneous and gut microbiomes have both been studied in relation to psoriasis. Patients with psoriasis—especially those with flaring psoriasis—may have different microbial fingerprints from those without psoriasis. The types of bacteria, yeast, or fungi that are growing, as well as the diversity of those species, appear to vary in interesting ways. For instance, microbial profiles on psoriatic skin are substantially different from those on healthy skin. Thus, local perturbations of the microbiome in someone with a genetic predisposition to psoriasis could promote the development of psoriasis. The same theory can be advanced for the gut microbiome (ie, do perturbations or alterations in the gut flora somehow get transmitted to other tissues in the body, including the skin and joints?).

Both theories are quite viable, in my opinion. In a patient with psoriasis, their immune system is inappropriately activated, and it is often possible to identify an environmental insult. For example, we know that certain drugs (eg, lithium or beta blockers) or certain infections (eg, group A streptococcal pharyngitis) can trigger psoriasis. If we extend this concept to changes in the gut or skin microbiome, a shift in the microbial composition could activate the immune system in an individual with a matching genetic predisposition. Gut immune system activation alone could become systemic and be transmitted to the skin through the action of cytokines and immune cell migration to the lymph nodes. Inappropriate immune system activation would become chronic without commensurate feedback loops that suppress such immune system activation.

Ultimately, treating a patient by normalizing the microbiome is a very attractive concept, but it is not yet feasible. We need a more sophisticated understanding of what constitutes a normal microbiome in a person who is predisposed to psoriasis. Although there is an interest in the use of probiotics, this is currently an imprecise approach because we do not know if a given probiotic will normalize the gut microbiota in a way that will help patients with psoriasis. In the future, we might be able to tailor therapeutic approaches to include oral supplementation or another intervention that reverts the patient’s microbiome to a healthier state and leads to immune system deactivation.


Atabati H, Esmaeili S-A, Saburi E, et al. Probiotics with ameliorating effects on the severity of skin inflammation in psoriasis: evidence from experimental and clinical studies. J Cell Physiol. 2020;235(12):8925-8937. doi:10.1002/jcp.29737

Chang H-W, Yan D, Singh R, et al. Multiomic analysis of the gut microbiome in psoriasis reveals distinct host‒microbe associations. JID Innov. 2022;2(3):100115. doi:10.1016/j.xjidi.2022.100115

Chen G, Chen Z-M, Fan X-Y, et al. Gut-brain-skin axis in psoriasis: a review. Dermatol Ther (Heidelb). 2021;11(1):25-38. doi:10.1007/s13555-020-00466-9

Lønnberg AS, Skov L, Skytthe A, Kyvik KO, Pedersen OB, Thomsen SF. Heritability of psoriasis in a large twin sample. Br J Dermatol. 2013;169(2):412-416. doi:10.1111/bjd.12375

Moludi J, Fathollahi P, Khedmatgozar H, et al. Probiotics supplementation improves quality of life, clinical symptoms, and inflammatory status in patients with psoriasis. J Drugs Dermatol. 2022;21(6):637-644. doi:10.36849/jdd.6237

Myers B, Vidhatha R, Nicholas B, et al. Sleep and the gut microbiome in psoriasis: clinical implications for disease progression and the development of cardiometabolic comorbidities. J Psoriasis Psoriatic Arthritis. 2021;6(1):27-37. doi:10.1177/2475530320964781

Polak K, Bergler-Czop B, Szczepanek M, Wojciechowska K, Fratczak A, Kiss N. Psoriasis and gut microbiome—current state of art. Int J Mol Sci. 2021;22(9):4529. doi:10.3390/ijms22094529

Quan C, Chen X-Y, Li X, et al. Psoriatic lesions are characterized by higher bacterial load and imbalance between Cutibacterium and Corynebacterium. J Am Acad Dermatol. 2020;82(4):955-961. doi:10.1016/j.jaad.2019.06.024

Schett G, Rahman P, Ritchlin C, McInnes IB, Elewaut D, Scher JU. Psoriatic arthritis from a mechanistic perspective. Nat Rev Rheumatol. 2022;18(6):311-325. doi:10.1038/s41584-022-00776-6

Song G, Yoon HY, Yee J, Kim MG, Gwak HS. Antihypertensive drug use and psoriasis: a systematic review, meta- and network meta-analysis. Br J Clin Pharmacol. 2022;88(3):933-941. doi:10.1111/bcp.15060

Thye AY-K, Bah Y-R, Law JW-F, et al. Gut-skin axis: unravelling the connection between the gut microbiome and psoriasis. Biomedicines. 2022;10(5):1037. doi:10.3390/biomedicines10051037

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