Where your DNA places you among other people, and the studies behind it.
Not tailored to your result, and not medical advice
Quit Smoking and Limit Alcohol: A 2026 dose-response meta-analysis of 30 observational studies found smokers had about 1.67 times the risk of developing psoriasis compared with non-smokers (95% CI 1.46 to 1.90), pooled across 15 studies and nearly 18 million people. Risk tracked cumulative exposure, rising from roughly 1.25 times at 10 pack-years to 1.70 times at 30 pack-years, and former smokers still sat at 1.38 times the risk of never smokers. The same review linked higher alcohol intake to psoriasis (1.33 times, attenuating to 1.19 once publication bias was accounted for). These are observational associations rather than proof of cause, and the authors concluded that smoking shows the stronger and more consistent association of the two, supported by that dose-response pattern, while the alcohol signal is smaller and less consistent. Frontiers in Public Health (PMC)
Work Toward a Healthy Weight: A systematic review pooled 13 randomised trials of weight-loss programs in 1,145 people who already had psoriasis. Participants lost about 6.9 kg more than controls, and their PASI severity score fell by 2.5 points more (95% CI 1.1 to 3.8), with 1.6 times the chance of reaching a 75% improvement in severity. Most of the trials tested low-calorie or energy-restricted diets on their own, or diets combined with physical activity. The authors rated certainty high for the overall severity change and only moderate for the larger response thresholds, and these trials measured severity in existing disease, not prevention. Journal of the European Academy of Dermatology and Venereology (PMC)
Track Your Own Flare Triggers: In the PSODEEP1 survey of 2,716 people with psoriasis in Chile, Denmark, the Netherlands and Sweden, 71% could name something that set off their flares. Stress dominated at 55.3%, followed by infections at 17.7%, alcohol at 10.8%, diet at 9.1%, weather at 7.1% and weight gain at 5.5%. Skin injury, the Koebner phenomenon in which new plaques appear at cuts, scratches or tattoo sites, was reported by 2.7%, and 65% noticed seasonal variation in their symptoms. Triggers are personal, so keeping a short record of flares alongside stress, illness, sleep and alcohol tends to be more useful than any general list. Acta Dermato-Venereologica (PMC)
Take New Joint Pain Seriously: Psoriasis and joint disease travel together more often than most people expect. A meta-analysis of 266 studies covering 976,408 patients with psoriasis put the pooled prevalence of psoriatic arthritis at 19.7% (95% CI 18.5% to 20.9%), reaching 22.7% in European cohorts and 14.0% in Asian ones. Persistent joint pain, swelling, morning stiffness, or a whole finger or toe swelling up are worth describing to a doctor rather than putting down to ordinary wear and tear. Raising it early is the point, because a clinician is the one who can sort out what is causing it. Journal of the American Academy of Dermatology (PubMed)
Be Realistic About Diet Claims: Psoriasis is immune-mediated, and no eating pattern has been shown to prevent it. A review in the American Journal of Clinical Dermatology concluded that only "based on low-quality data, select foods and dietary patterns may affect psoriasis", with the clearest signal being weight loss in people whose BMI is elevated. Going gluten-free appeared to help mainly the subset who have celiac disease or test positive for antigliadin antibodies, and the review found the evidence for oral vitamin D in treating or preventing psoriasis lacked high-quality support. Mediterranean-style eating is the pattern with the strongest supporting evidence in that review, and it also addresses the cardiovascular and metabolic problems that commonly accompany psoriasis. American Journal of Clinical Dermatology (PMC)
How much of this is genetic?
Genetics explains 68% of why people differ in this trait. The rest is environment, daily habits and chance.
Heritability estimate: Lønnberg et al. 2013, British Journal of Dermatology
Background and further reading
Psoriasis is a chronic, immune-mediated inflammatory disease that primarily affects the skin, where accelerated turnover of skin cells produces raised, red, well-demarcated plaques covered with silvery scale, classically on the scalp, elbows, knees, and lower back. It affects roughly 2 to 3 percent of people worldwide, with onset most common in early adulthood and a smaller second peak later in life. The most frequent form is plaque psoriasis (psoriasis vulgaris), but other patterns include guttate, inverse, pustular, and erythrodermic disease. Psoriasis is not contagious. It is a systemic condition rather than a purely skin problem: up to about a third of people develop psoriatic arthritis, and psoriasis is associated with a higher likelihood of cardiovascular and metabolic disease.
Genetic Basis: Psoriasis is one of the more heritable common inflammatory conditions. Twin studies show much higher concordance in identical than non-identical twins, and a large Danish twin study estimated that genetic factors explain roughly two-thirds of the variation in susceptibility. The single strongest genetic determinant is the PSORS1 locus within the major histocompatibility complex on chromosome 6p21, where the HLA-C*06:02 allele confers the largest common-variant effect and is especially linked to early-onset and guttate disease. Beyond HLA, genome-wide association studies have identified dozens of loci that converge on the interleukin-23 / T-helper-17 (Th17) immune axis and on skin-barrier and innate-immune signaling, including IL12B, IL23R, IL23A, TNIP1, TNFAIP3, and TRAF3IP2. The centrality of the IL-23/IL-17 pathway is underscored by the clinical success of biologic therapies that target these cytokines.
Environmental Factors: Genetic predisposition sets the stage, but environmental and lifestyle triggers strongly influence whether psoriasis appears and how severe it becomes. Streptococcal throat infection is a well-recognized trigger of guttate psoriasis, particularly in younger people. Skin injury can provoke new plaques at the site of trauma, a pattern known as the Koebner phenomenon. Cigarette smoking and higher body weight are consistently associated with greater risk and severity, and heavy alcohol use, psychological stress, and certain medications (including beta-blockers, lithium, antimalarials, and abrupt withdrawal of systemic corticosteroids) can precipitate or worsen flares. Because these factors are modifiable, they are meaningful targets for people managing the condition.
The published research behind your score, and the variants it draws on.
11 published scores from 3 studies
The psoriasis score combines 11 polygenic scores drawn from 3 published studies.
Nair PA, Badri T. Psoriasis. StatPearls (NCBI Bookshelf) (2023)
These traits are influenced by some of the same genes and variants as this one
Crohn's Disease: Chronic inflammatory bowel disease affecting the digestive tract lining.
Content updated August 2026.
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