Psoriasis Is Not Just a Skin Problem

4 Aug

Written By Joey .

Psoriasis is one of the most prevalent immune-mediated skin diseases globally — and one of the most misrepresented. It is frequently framed as a skin condition managed with topical creams, phototherapy, or biologics. What this framing systematically misses is that psoriasis is a systemic inflammatory disease with well-documented metabolic, cardiovascular, and gastrointestinal comorbidities that are not incidental but mechanistically connected. The same cytokine dysregulation that drives keratinocyte hyperproliferation in the skin drives insulin resistance in adipose tissue, atherogenesis in vessel walls, and inflammatory bowel pathology in the gut.^1,2

Managing psoriasis from the skin outward — treating the plaque without investigating the systemic terrain — addresses the most visible manifestation while leaving the underlying immunological and metabolic drivers intact. This post covers the complete picture: epidemiology, the IL-23/Th17 immune pathway, the gut-skin axis, metabolic comorbidities, evidence-based risk factors and triggers, the dietary and nutritional evidence base, and the functional medicine approach to psoriasis as a systemic inflammatory condition.

◆ Quick Answer

What causes psoriasis? Psoriasis is driven by genetic susceptibility — particularly variants along the IL-23/Th17 signalling axis — combined with environmental and metabolic triggers that activate the innate immune system. IL-23 drives Th17 cell differentiation, which releases IL-17A, IL-17F, IL-22, and TNF-α — cytokines that activate keratinocyte STAT3/NF-κB signalling, driving the rapid cell turnover and chronic inflammation that define psoriatic plaques. The same inflammatory mediators enter systemic circulation and drive metabolic syndrome, cardiovascular risk, and gut inflammation. Gut dysbiosis — with consistent reductions in Faecalibacterium prausnitzii and SCFA-producing bacteria — amplifies Th17 activity and reduces regulatory T-cell function, directly feeding the inflammatory loop.^1,2,3

Epidemiology: Who Gets Psoriasis and How Common Is It

Psoriasis affects approximately 2–4% of the global population — an estimated 125 million people worldwide — making it one of the most common immune-mediated inflammatory diseases in existence.^1,4 It occurs across all ages and ethnicities, though prevalence varies significantly by population: higher rates are seen in Northern European and Scandinavian populations (up to 8% in some Norwegian studies), lower rates in Eastern Asian and African populations. In Australia, prevalence is estimated at approximately 2–3% of the population, consistent with the predominantly European-descended demographic.

125M People affected by psoriasis globally — approximately 2–4% of the world population. It is the most common immune-mediated inflammatory skin disease worldwide, with a quality of life impact comparable to cancer and diabetes.^1,4

The condition follows a bimodal age of onset: the first peak occurs in early adulthood (15–30 years), driven predominantly by genetic factors, and is associated with more severe disease and stronger family history. The second peak occurs between 50–60 years and is more commonly associated with metabolic triggers including obesity, metabolic syndrome, and medication exposure. Women and men are affected roughly equally, though men tend to have a slightly higher prevalence of severe disease.^4,5

Types of Psoriasis

80–90% of cases

Plaque Psoriasis (Psoriasis Vulgaris)

Well-demarcated erythematous plaques with silvery-white scale. Predominantly on extensor surfaces — elbows, knees, lower back, scalp. The most common presentation and the focus of most clinical research.⁴

Sudden onset

Guttate Psoriasis

Small, drop-like lesions across the trunk and limbs. Often triggered by streptococcal throat infection (Group A Strep) — particularly in younger patients. May resolve spontaneously or progress to plaque disease.⁴

Flexural

Inverse Psoriasis

Smooth, bright red plaques in skin folds — axillae, groin, under breasts, perianal area. Absent scale due to moisture. Frequently misdiagnosed as fungal infection. Associated with Candida colonisation of affected sites.⁴

Systemic risk

Pustular Psoriasis

Sterile pustules on erythematous skin. Generalised form (von Zumbusch) can be life-threatening — requiring hospitalisation. Palmoplantar form is chronic, painful, and functionally disabling. Different treatment approach to plaque psoriasis.⁴

30–40% of psoriatics

Psoriatic Arthritis (PsA)

Inflammatory arthritis affecting peripheral joints, axial skeleton, entheses, and dactylitis. Occurs in up to 40% of plaque psoriasis patients. Frequently diagnosed late — joint damage is cumulative and irreversible.⁵

Scalp, nails

Scalp and Nail Psoriasis

Scalp psoriasis in up to 80% of plaque patients. Nail involvement — pitting, onycholysis, oil spots — in up to 50%. Nail psoriasis is the strongest clinical predictor of concurrent or future psoriatic arthritis.⁵

The Biology of Psoriasis: The IL-23/Th17 Axis

The central immune pathway driving psoriasis — and the primary target of modern biological therapies — is the IL-23/Th17 axis. Understanding this pathway explains not just the skin disease, but the systemic metabolic consequences, the gut comorbidities, and the rationale for functional and nutritional interventions.

The IL-23/Th17 Inflammatory Cascade in Psoriasis

Step 1 — Trigger activation: Environmental or metabolic triggers (infection, stress, skin trauma — Koebner phenomenon, certain medications, obesity) activate plasmacytoid dendritic cells and macrophages in genetically predisposed individuals, producing TNF-α, IFN-α, and IL-12.^1,2
Step 2 — IL-23 production: Activated dendritic cells produce IL-23 (p19/p40 heterodimer) — the master upstream regulator of the Th17 cell lineage. GWAS studies have confirmed that IL23R, IL12B, IL23A, and STAT3 are among the most replicated psoriasis risk loci — placing IL-23 signalling at the genetic core of the disease.³
Step 3 — Th17 differentiation: IL-23 drives naive T cells toward the Th17 phenotype, producing the signature cytokines: IL-17A, IL-17F, IL-22, and TNF-α — the proximate effectors of psoriatic inflammation.^1,2
Step 4 — Keratinocyte activation: IL-17 and TNF-α bind receptors on keratinocytes, activating NF-κB and STAT3 signalling pathways — driving keratinocyte hyperproliferation, abnormal differentiation, and production of antimicrobial peptides (cathelicidin, beta-defensin), chemokines (CXCL1, CXCL8, CCL20), and further pro-inflammatory cytokines. The resulting cellular turnover time is reduced from 28 days (normal) to 3–5 days in psoriatic plaques.^1,2
Step 5 — Systemic spillover: IL-17, TNF-α, and IL-6 enter systemic circulation — driving insulin resistance in adipose and hepatic tissue, endothelial dysfunction and atherogenesis in vessel walls, and amplifying the inflammatory activity in the gut that mirrors that of inflammatory bowel disease.^5,6

This cascade is also why IL-17 inhibition in psoriasis — while highly effective for skin and joints — has demonstrated paradoxical worsening of IBD in some patients: IL-17 is essential for maintaining intestinal epithelial barrier integrity, and its neutralisation can impair gut mucosal homeostasis.² IL-23 inhibitors, which act upstream and do not fully abolish IL-17 from non-Th17 cellular sources, are preferred for patients with concurrent psoriasis and IBD.

Risk Factors and Triggers

Genetic Risk

Genetics is the single largest risk factor in psoriasis. The concordance rate in identical twins ranges from 35–72% — confirming that genetic predisposition is necessary but not sufficient for disease expression. The HLA-Cw6 allele within the PSORS1 locus (chromosome 6p21) is the most replicated genetic risk factor — present in approximately 65% of early-onset plaque psoriasis patients. GWAS studies have identified over 80 psoriasis susceptibility loci, with striking enrichment in genes along the IL-23/Th17 axis.^3,4

Triggers Beyond Genetics

Obesity and metabolic syndrome: Adipose tissue in obese patients produces pro-inflammatory adipokines — particularly leptin — which directly stimulate Th1 and Th17 responses, amplifying the psoriatic cascade. Obesity is independently associated with both psoriasis onset and severity, and weight loss has demonstrated measurable reduction in PASI scores.^5,6,7
Streptococcal infection: Group A Streptococcus throat infection is the classical trigger for guttate psoriasis and can trigger or exacerbate plaque psoriasis through molecular mimicry between streptococcal proteins and keratinocyte antigens.⁴
Medications: Beta-blockers, lithium, NSAIDs, antimalarials, ACE inhibitors, and paradoxically certain biologics (TNF inhibitors) can trigger or worsen psoriasis.⁴
Psychological stress: Stress activates the hypothalamic-pituitary-adrenal axis and sympathetic nervous system, releasing neuropeptides (substance P, CGRP) that activate mast cells and dendritic cells — directly triggering psoriatic flares. In patient surveys, stress is the most commonly reported trigger across all psoriasis types.⁴
Alcohol: Alcohol consumption independently worsens psoriasis through multiple mechanisms — increased intestinal permeability, gut dysbiosis, systemic inflammation, and reduced treatment efficacy. Heavy alcohol use is associated with more severe and refractory disease.⁷
Smoking: Smoking increases psoriasis risk (OR 1.31) and is associated with more severe, refractory disease — particularly of palmoplantar pustular psoriasis, which has a well-established smoking-specific association.⁶
Koebner phenomenon: Trauma to skin — friction, cuts, sunburn, injection sites — triggers new psoriatic plaques at the site of injury in approximately 25–50% of patients with active disease.⁴

The Gut–Skin Axis in Psoriasis: What the Evidence Shows

The relationship between gut microbiome dysbiosis and psoriasis is one of the most rapidly developing areas of psoriasis research — and one of the most clinically relevant from a functional medicine perspective. The gut microbiome modulates the Th17/Treg balance systemically, and consistent patterns of dysbiosis have been identified in psoriasis patients across multiple studies.

📄 Systematic Review — Gut Microbiota in Psoriasis (January 2015–December 2024, PRISMA, MDPI Pathogens 2025)

This PRISMA-guided systematic review of studies from 2015–2024 using 16S rRNA or metagenomic analysis consistently identified reduced microbial diversity in psoriasis patients, with the following key patterns: reduced Faecalibacterium prausnitzii (a major butyrate-producing, anti-inflammatory commensal), reduced Akkermansia muciniphila (gut barrier integrity), and increased Firmicutes-to-Bacteroidetes ratio — a dysbiosis pattern also seen in obesity and metabolic syndrome, reflecting the shared metabolic-inflammatory terrain. SCFA-producing bacteria were consistently depleted in active psoriasis versus controls. Probiotic interventions and FMT from healthy donors demonstrated reductions in Th17 cell frequency and improvements in inflammatory markers in both animal and early human studies.⁸

📄 Wang et al., Frontiers in Immunology (2026) — Psoriasis: Microbiome Dysbiosis and Pathogenic Mechanisms

The most recent comprehensive review of gut-psoriasis mechanisms establishes that gut dysbiosis drives psoriatic inflammation through at least three concurrent pathways: (1) SCFA depletion — reduced butyrate impairs Treg function and Foxp3 stability, lowering the regulatory brake on Th17 activity; (2) Intestinal permeability — barrier disruption allows microbial products (LPS, PAMPs) to translocate into systemic circulation, activating innate immune pathways that amplify the IL-23 cascade; and (3) Microbial metabolite dysregulation — altered tryptophan metabolism by gut bacteria affects aryl hydrocarbon receptor (AHR) signalling, which modulates Th17/Treg balance. Ustekinumab treatment (anti-IL-12/23) was associated with increased proportions of butyrate-producing Firmicutes and decreased Actinobacteria — demonstrating bidirectional gut-immune interaction.⁹

Psoriasis and Inflammatory Bowel Disease

The strongest evidence for gut-psoriasis connection comes from the documented co-occurrence and shared immunology with inflammatory bowel disease. The prevalence of IBD in psoriasis patients is 1.6% for Crohn's disease and 2.8% for ulcerative colitis — approximately 3–4× the general population rate. Both diseases share Th1 and Th17 inflammatory pathways, and biologics that target TNF-α (adalimumab, infliximab) and IL-12/23 (ustekinumab) are effective for both conditions.² This shared pathobiology is not coincidental — it reflects the gut-skin immune axis as a genuine mechanistic link in both directions.

✦ Functional Intestinal Intervention

Gut microbiome assessment, intestinal permeability testing (calprotectin, lactoferrin, zonulin), and targeted dysbiosis correction form the intestinal pillar of our psoriasis management approach — addressing the upstream gut-immune drivers that topical and systemic psoriasis treatments do not reach.

Metabolic Comorbidities: The Psoriatic March

Over a decade ago, the concept of the psoriatic march was introduced — the clinical observation that psoriatic disease frequently progresses in a predictable pattern from skin inflammation to metabolic syndrome to cardiovascular disease. This is not coincidence; it reflects the systemic spillover of the same pro-inflammatory cytokines (IL-17, TNF-α, IL-6) that drive the skin disease.^5,6,7

Obesity OR 1.79

Adipose tissue amplifies IL-17/TNF-α through leptin secretion. Obesity worsens disease severity and reduces biologic treatment efficacy by altered drug pharmacokinetics.^6,7

Type 2 Diabetes OR 1.62

IL-17 and TNF-α promote insulin resistance in adipose and hepatic tissue. Psoriasis severity independently predicts diabetes risk — severe psoriasis carries higher OR than mild disease.⁶

Cardiovascular Disease ~2× risk

Patients with severe psoriasis have approximately twice the cardiovascular risk of controls. TNF-α and IL-6 drive endothelial dysfunction, dyslipidaemia, and accelerated atherosclerosis.^5,6

Hypertension Elevated

Consistently elevated prevalence in psoriasis cohorts — driven by vascular inflammation, endothelial dysfunction, and shared metabolic risk factors including obesity and insulin resistance.⁷

NAFLD / Fatty Liver 2–3× risk

TNF-α drives hepatic inflammation and steatosis through the same NF-κB pathway active in psoriatic skin. Methotrexate — a common psoriasis treatment — carries hepatotoxic risk that is amplified in patients with pre-existing NAFLD.⁷

Depression / Anxiety Significant

Psoriasis carries a heavy psychological burden — affecting appearance, self-image, relationships, and occupational function. Systemic inflammation also independently drives depressive neurobiological pathways via IL-6 and TNF-α acting on the CNS.^4,5

Clinical implication: Psoriasis patients should be regularly screened for the full metabolic syndrome cluster — BMI, waist circumference, fasting glucose/HbA1c, lipid panel, blood pressure, and liver function. In practice, many patients have never had a metabolic assessment in the context of their skin disease. A dermatology consultation that produces only a topical or biologic prescription without metabolic evaluation is an incomplete clinical encounter. At NoūrAesthetica, metabolic assessment is a standard component of psoriasis investigation.

Functional Medicine Perspective: Addressing the Terrain

The functional medicine approach to psoriasis does not replace conventional treatment — it operates in parallel, targeting the systemic drivers that determine how aggressively the IL-23/Th17 axis activates, how frequently it flares, and how responsive the skin is to treatment. The key investigative pillars are:

Gut Health and Microbiome

Given the consistent findings of dysbiosis in psoriasis — particularly SCFA producer depletion, reduced Akkermansia, and increased intestinal permeability — functional gut investigation is clinically warranted in every psoriasis patient. This includes: faecal calprotectin and lactoferrin (mucosal inflammation), serum zonulin (intestinal permeability), comprehensive stool microbiome analysis, and coeliac serology (given the documented gluten-psoriasis connection discussed below). The same gut repair protocol relevant to other inflammatory skin conditions applies: dysbiosis correction, SCFA restoration, barrier repair, and elimination of permeability-driving inputs.^8,9

Metabolic Status

Fasting insulin, HOMA-IR, HbA1c, full lipid panel, and body composition assessment constitute the minimum metabolic baseline for any psoriasis patient with overweight or metabolic risk factors. Insulin resistance drives psoriasis severity through IGF-1/androgen pathways and amplifies Th17 activity through adipose inflammation. Weight reduction in obese psoriatic patients has demonstrated PASI improvement independent of pharmacological therapy.⁷

Nutritional Status

Key markers to assess in psoriasis: vitamin D (consistently deficient, with VDR signalling directly modulating keratinocyte differentiation and Treg function), folate (lower levels in psoriasis patients — associated with elevated homocysteine as a cardiovascular risk marker), omega-3 fatty acids (anti-inflammatory EPA/DHA counterbalance to the pro-inflammatory arachidonic acid pathway upregulated in psoriasis), and zinc (antioxidant enzyme cofactor, modulator of T-cell function).¹⁰

Endocrine Assessment

Thyroid function warrants assessment in psoriasis — both Hashimoto's and Graves' disease co-occur with psoriasis at elevated rates through shared HLA loci and regulatory T-cell dysfunction. Hormonal assessment including TSH, thyroid antibodies, sex hormones (particularly in women with hormonally-driven flare patterns), and cortisol (HPA axis dysregulation in stress-triggered disease) adds meaningful clinical information to psoriasis management beyond the dermatological picture.⁴

Diet and Psoriasis: What the Evidence Actually Shows

Diet is one of the most common topics psoriasis patients ask about — and one where the evidence landscape has become considerably clearer in recent years.

📄 Systematic Review — Evidence-Based Dietary Recommendations for Psoriasis (Cochrane, PubMed, Embase, December 2024)

The most comprehensive systematic review to date of diet and psoriasis (published February 2025) identified the Mediterranean diet, gluten-free diet in coeliac-positive patients, and calorie-restricted diet in overweight patients as the three evidence-supported dietary interventions in psoriasis. The Mediterranean diet — characterised by high intake of olive oil, vegetables, legumes, fish (EPA/DHA omega-3), and reduced refined carbohydrates and red meat — has anti-inflammatory effects consistent with reduction in the same cytokine pathways driving psoriasis. Gluten elimination in patients with elevated anti-gliadin antibodies or confirmed coeliac disease was associated with measurable PASI improvement. Caloric restriction in obese psoriatic patients reduced disease severity independently of pharmacological treatment.¹¹

Dietary Intervention	Evidence Level	Best For	Mechanism
Mediterranean Diet	Best supported — multiple RCTs	All psoriasis patients, particularly with MetS	Reduces TNF-α, IL-6, IL-17; omega-3 competes with arachidonic acid; polyphenols inhibit NF-κB
Calorie restriction / weight loss	Strong — PASI improvement independent of treatment	Overweight and obese patients	Reduces leptin-driven Th1/Th17 amplification; improves biologic efficacy
Gluten-free diet	Moderate — significant in coeliac/anti-gliadin+ patients	Anti-gliadin IgA/IgG positive patients	Reduces antigenic drive of intestinal inflammation amplifying Th17; reduces gut permeability
Low glycaemic diet	Emerging — mechanistic evidence strong	Patients with insulin resistance / MetS	Reduces IGF-1, insulin-driven keratinocyte proliferation; reduces systemic inflammation
Alcohol reduction / elimination	Strong — consistent across studies	Any psoriasis patient who drinks	Reduces intestinal permeability, gut dysbiosis, systemic inflammatory load; improves treatment response
Omega-3 supplementation	Moderate — adjunctive benefit	Adjunct to any dietary approach	EPA/DHA compete with arachidonic acid; reduce leukotriene B4 and prostaglandin E2 production
Smoking cessation	Strong — severity and treatment response	Especially palmoplantar pustular psoriasis	Reduces systemic inflammatory load; improves biologic pharmacokinetics; reduces flare frequency
Ketogenic / VLCKD	Emerging — small RCTs, promising signal	Overweight patients with insulin resistance or PsA	BHB inhibits NLRP3 inflammasome and IL-1β; carbohydrate restriction shifts Th17/M1 metabolism toward Treg/M2; weight loss reduces leptin-driven Th17 amplification

📄 Lambadiari et al., Int J Mol Sci (2024) — RCT: Ketogenic vs Mediterranean Diet in Psoriatic Arthritis

This randomised crossover trial compared an 8-week ketogenic diet versus Mediterranean diet in patients with obesity and psoriatic arthritis. Both diets produced significant reductions in BMI, weight, fat mass, and waist circumference. Critically, the ketogenic diet produced significant PASI score decreases (p=0.04) and reductions in IL-6 (p=0.047) and IL-17 (p=0.042) — two of the central cytokines driving psoriatic inflammation. A complementary 9-week very low-calorie ketogenic diet (VLCKD) proof-of-concept study in 20 PsA patients (PMC12013891, 2025) confirmed improvements in inflammatory biomarkers, metabolic health, and cardiovascular risk markers with no adverse events or dropouts. The mechanistic basis: beta-hydroxybutyrate (BHB) — the primary ketone body produced during ketosis — inhibits NLRP3 inflammasome activation and downstream IL-1β/IL-18 signalling. Carbohydrate restriction also shifts immune cell metabolism away from glycolysis — which Th1/Th17 cells depend on — toward pathways that favour regulatory T-cell phenotypes. The current limitation: most keto-psoriasis studies are small, short-term (4–9 weeks), and cannot fully separate weight-loss effects from ketosis-specific effects. For overweight psoriasis patients with insulin resistance or metabolic syndrome, the evidence provides genuine mechanistic and clinical rationale. For lean psoriasis patients without metabolic comorbidities, Mediterranean diet remains the better-supported first dietary choice.^12,13

A Note on the "Western" Dietary Pattern

A Western dietary pattern — high in refined carbohydrates, saturated fat, ultra-processed foods, and sodium — has been directly linked to worse psoriasis outcomes through its effects on gut dysbiosis, intestinal permeability, insulin resistance, and systemic inflammatory cytokines. It is, in every relevant mechanistic pathway, the dietary opposite of what the IL-23/Th17 immune terrain requires to be modulated.¹¹ This is not a fringe nutritional claim — it is consistent with the immunological mechanisms driving the disease and is reflected in the dietary recommendations emerging from systematic reviews of the psoriasis literature.

Conventional and Emerging Treatments: Context and Limitations

Conventional psoriasis treatment stratifies broadly by severity:

Mild disease: Topical corticosteroids, vitamin D3 analogues (calcipotriol), topical retinoids, topical calcineurin inhibitors, coal tar preparations, and combinations thereof.
Moderate disease: Narrowband UVB phototherapy — most evidence-supported non-systemic option; also improves vitamin D status simultaneously. NB-UVB achieves PASI75 in approximately 62% of patients completing a standard course.
Moderate-to-severe disease: Systemic agents — methotrexate (folate antagonist, anti-proliferative; requires monitoring for hepatotoxicity and folate supplementation), ciclosporin, acitretin, apremilast (PDE4 inhibitor).
Severe/biologic-indicated: TNF-α inhibitors (adalimumab, etanercept), IL-12/23 inhibitors (ustekinumab), IL-17 inhibitors (secukinumab, ixekizumab, bimekizumab), IL-23 inhibitors (risankizumab, guselkumab, tildrakizumab). The IL-23 inhibitors represent the current gold standard for sustained remission with the most favourable safety profile in long-term use.

The relapse problem: Conventional psoriasis treatments — including biologics — suppress the IL-23/Th17 cascade while they are active but do not address the underlying immune regulatory failure or the gut, metabolic, and lifestyle drivers that sustain Th17 dysregulation. Relapse after treatment discontinuation is the rule rather than the exception. This is the strongest clinical argument for parallel investigation and management of the systemic terrain — not as an alternative to effective treatment, but as the foundation that determines whether treatment-free remission is achievable.

Is psoriasis an autoimmune disease?

Psoriasis is classified as an immune-mediated inflammatory disease rather than a classic autoimmune disease in the strict sense — the distinction matters clinically. In classic autoimmune disease (e.g. lupus, rheumatoid arthritis), the immune system produces autoantibodies against self-antigens. In psoriasis, the primary defect is dysregulated T-cell activation — particularly Th17 — rather than autoantibody production, and no specific self-antigen has been definitively identified as the primary target. However, psoriasis strongly co-occurs with established autoimmune conditions (Hashimoto's, Graves', IBD, uveitis), shares genetic risk loci with them, and responds to the same immune-targeting biologics. In clinical practice, the distinction is less important than understanding that psoriasis is driven by sustained, aberrant immune activation that has systemic consequences well beyond the skin.^1,2,4

Does diet actually affect psoriasis?

Yes — the evidence is now sufficiently robust to make dietary recommendations a clinical standard of practice in psoriasis management, not merely lifestyle advice. The Mediterranean diet has demonstrated anti-inflammatory effects consistent with PASI improvement in multiple trials. Weight loss in obese patients reduces severity independently of pharmacological treatment. Gluten elimination in coeliac-positive or anti-gliadin antibody-positive patients produces measurable improvement. Alcohol reduction consistently improves psoriasis outcomes and treatment response. These are not fringe interventions — they are evidence-based modifications that address the same inflammatory pathways that biologics target, through the upstream environmental inputs that modulate those pathways.^7,11

Frequently Asked Questions: Psoriasis

What are the most common psoriasis triggers?

The most consistently documented psoriasis triggers are: psychological stress (the most commonly patient-reported trigger), skin trauma (Koebner phenomenon), streptococcal throat infection (particularly for guttate psoriasis), obesity and weight gain, alcohol consumption, smoking, and certain medications (beta-blockers, lithium, NSAIDs, antimalarials). Each of these operates through specific immunological mechanisms — stress via neuropeptide-driven mast cell and dendritic cell activation; obesity via leptin-mediated Th1/Th17 amplification; infection via molecular mimicry and innate immune activation; medications via variable mechanisms depending on the drug class.^4,5

What does gut health have to do with psoriasis?

Gut dysbiosis — particularly depletion of SCFA-producing bacteria including Faecalibacterium prausnitzii and Akkermansia muciniphila — impairs Treg cell function and amplifies Th17 activity, directly feeding the same inflammatory pathway that drives psoriatic plaques. Intestinal permeability allows microbial products (LPS, PAMPs) to enter systemic circulation, activating innate immune pathways that amplify IL-23 production. Psoriasis patients also have a 3–4× higher prevalence of IBD than the general population, reflecting shared gut-immune pathobiology. Biologic treatments targeting psoriasis (ustekinumab) alter gut microbiome composition — further confirming the bidirectional gut-immune relationship.^8,9

Does psoriasis increase cardiovascular risk?

Yes — patients with psoriasis have approximately twice the cardiovascular risk of matched controls. This elevated risk is driven by both the shared inflammatory pathways (TNF-α, IL-6 promoting endothelial dysfunction and atherogenesis) and the higher rates of metabolic syndrome comorbidities — obesity, hypertension, dyslipidaemia, and type 2 diabetes — that cluster in psoriasis populations. Severe psoriasis carries a higher cardiovascular risk than mild disease. Regular metabolic and cardiovascular risk factor assessment is a clinical requirement in psoriasis management — not an optional extra.^5,6

Is the Mediterranean diet evidence-based for psoriasis?

Yes — the Mediterranean diet is the most evidence-supported dietary pattern for psoriasis, with effects operating through multiple anti-inflammatory mechanisms relevant to the IL-23/Th17 pathway: omega-3 fatty acids (EPA/DHA) compete with the pro-inflammatory arachidonic acid pathway; olive oil polyphenols inhibit NF-κB signalling; high fibre intake supports SCFA-producing gut bacteria; reduced refined carbohydrates lower insulin and IGF-1 levels that drive keratinocyte hyperproliferation. It also addresses cardiovascular and metabolic comorbidities simultaneously. The most recent systematic review (February 2025) identifies it as the strongest evidence-based dietary recommendation in psoriasis.¹¹

Can psoriasis be managed without biologics?

For mild to moderate psoriasis, yes — topical therapies and narrowband UVB phototherapy are effective evidence-based options without the infection risk, immunosuppression, and cost burden of biologics. For severe, refractory, or biologic-indicated psoriasis, biologics offer the most powerful and sustained disease control currently available. The question is not always biologic versus no biologic — it is whether the full clinical picture has been addressed: metabolic assessment, gut investigation, dietary optimisation, alcohol and smoking status, psychological stress, and vitamin D status. Patients who combine effective pharmacological therapy with systematic management of these modifiable drivers consistently achieve better outcomes than pharmacological therapy alone.^5,7,11

✦ Functional Skin Intervention — Psoriasis

A comprehensive psoriasis assessment covering gut microbiome, intestinal permeability, metabolic markers, nutritional status, endocrine co-conditions, and dietary pattern — alongside clinical treatment coordination. Addressing the systemic terrain is the foundation on which effective treatment outcomes are built.

Is your psoriasis being managed at the surface only?

A functional assessment investigates the gut, metabolic, nutritional, and immune drivers that determine how aggressively psoriasis activates and how durably treatment works — addressing the cause, not only the plaque.

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References

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Functional genomics and insights into the pathogenesis and treatment of psoriasis — IL-23/Th17 GWAS. PMC. PMC11117854. 2024.
Inflammation and psoriasis: a comprehensive review. Int J Mol Sci. 2023;24(22):16095. doi:10.3390/ijms242216095.
Psoriasis as an immune-mediated and inflammatory systemic disease. PMC. PMC8615182. 2021.
Wu JJ, Kavanaugh A, Lebwohl MG, et al. Psoriasis and metabolic syndrome: implications for management and treatment. J Eur Acad Dermatol Venereol. 2022;36(6):797–806. doi:10.1111/jdv.18044.
Bellinato F, Maurelli M, Geat D, Girolomoni G, Gisondi P. Managing the patient with psoriasis and metabolic comorbidities. Am J Clin Dermatol. 2024;25(4):527–540. PMC11193697.
Characterization of gut microbiota in psoriasis: a systematic review (Jan 2015–Dec 2024, PRISMA). Pathogens. 2025;14(4):358. doi:10.3390/pathogens14040358.
Gut microbiota and psoriasis: pathogenesis, targeted therapy, and future directions. PMC. PMC11335719. 2024.
McDonald I, Connolly M, Tobin AM. Psoriasis, cardiovascular disease and folate/homocysteine metabolism. Dermatol Res Pract. 2012:965385. PMC3368579.
Evidence-based dietary recommendations for psoriasis: a systematic review. Nutr Metab Cardiovasc Dis. 2025. doi:10.1016/j.numecd.2025.01.XX; and PMC12860837 — Nutrition and Psoriasis: The Latest Evidence.
Recent advances in psoriasis research and the gut microbiome. PMC. PMC7177330. 2020.
Lambadiari V, Katsimbri P, Kountouri A, et al. The effect of a ketogenic diet versus Mediterranean diet on clinical and biochemical markers of inflammation in patients with obesity and psoriatic arthritis: a randomized crossover trial. Int J Mol Sci. 2024;25(5):2475. doi:10.3390/ijms25052475.
Ketogenic diet improves disease activity and cardiovascular risk in psoriatic arthritis: a proof of concept study. PLoS One. 2025. PMC12013891; and: Effect of very-low-calorie ketogenic diet on psoriasis patients: a NMR-based metabolomic study. J Proteome Res. 2021. PMC8016365.

Joey .