A comprehensive review explains why psoriasis vulgaris (≈90% of psoriasis) often worsens in autumn to winter by linking environmental triggers—sun exposure, humidity, air pollution, and circadian disruption—to molecular pathways. Ultraviolet light influences keratinocyte turnover and immune signaling. Low humidity increases transepidermal water loss. Particulate matter and NO₂ drive oxidative stress. Circadian disruption likely aggravates disease via reduced sunlight/vitamin D and melatonin. Smoking further exacerbates psoriasis, and patients have higher rates of asthma and sleep apnea, aligning with the disorder’s systemic burden. The authors note that geography and local climate can meaningfully alter these exposures and should inform individualized counseling.

Surveying studies through March 10, 2024, the authors propose that seasonal gene-expression and epigenetic shifts amplify inflammation under adverse conditions. Clinically, they recommend season-aware management: emollients and humidification in dry months, phototherapy or safe sunlight exposure, air-quality mitigation, and sleep–wake regularity. They urge integrated research combining environmental metrics with omics and clinical data to personalize timing and intensity of therapy and improve adherence. They also call for prospective, regionally diverse studies and clear patient “seasonal action plans” to translate these insights into routine care.

Reference: Nowosielski B. Environmental Factors Impact Psoriasis Severity. Drug Topics. Published April 8, 2025. Accessed October 27, 2025. https://www.drugtopics.com/view/environmental-factors-impact-psoriasis-severity

Researchers of a multicenter, retrospective study of 1024 adults with moderate-to-severe psoriasis treated with guselkumab (2019-2024) showed rapid and durable skin clearance in routine practice. Mean Psoriasis Area and Severity Index (PASI) scores fell from 14.3±8.8 at baseline to 1.3±2.4 at 6 months and remained low from 12 to 60 months (≈1.0–1.3). Drug survival was high, with Kaplan–Meier estimates of 95.85%, 91.73%, 89.74%, 87.08%, and 85.76% at 12, 24, 36, 48, and 60 months, respectively.

Response was attenuated in several subgroups: patients with prior biologic exposure, those with obesity, and those switched from anti-IL-17 therapies had significantly lower PASI responses across time points. In multivariable models, previous biologic use and obesity were consistent negative predictors of achieving PASI 75/90/100; cardiovascular disease predicted lower odds of PASI 90 at 3 months (OR 0.64, 95% CI 0.42–0.97). Risk of discontinuation was higher in females, individuals with ≥3 prior biologics, longer disease duration, and prior anti-IL-17 therapy, while overall comorbidity burden did not significantly affect discontinuation. Overall, guselkumab demonstrated sustained long-term effectiveness and persistence, with patient history and metabolic factors informing prognosis. As a retrospective, nonrandomized analysis, these findings may be influenced by selection bias, unmeasured confounding, and missing data, and safety outcomes were not detailed.

Reference: Mortato E, Talamonti M, Marcelli L, et al. Long-Term Real-World Effectiveness and Drug Survival of Guselkumab in Patients with Psoriasis: A 5-Year Retrospective Study. Psoriasis (Auckl). 2025;15:455-469. doi: 10.2147/PTT.S533005.

Researchers of a Finnish real-world study (2013–2021) analyzed 2,437 adults with plaque psoriasis who purchased biologic therapies, following patients from first biologic initiation (“first biological cohort,” n=2,092) or biologic switch (“switchers,” n=345) through 2022. Within one year of starting a first biologic, 12.5% switched. In the initiation cohort, work absences rose before treatment start and declined afterward. Among switchers, work absences were modest and more linear. Disability pensions were slightly more common in switchers (<65 years: 7.8%) than in initiators (6.6%), and 86 initiators (4.1%) and 11 switchers (3.2%) were already receiving disability pensions before treatment began.

Healthcare use fell meaningfully after first biologic initiation: all-cause outpatient contacts (11.1 vs 7.4 per patient-year) and disease-related inpatient days (0.46 vs 0.16) decreased, and disease-related contact costs dropped from €2,098 to €1,094 per patient-year (all p<0.001). In contrast, switchers did not show significant healthcare utilization reductions, underscoring persistent unmet needs in patients who require multiple biologics. These observational findings suggest earlier, effective biologic use may reduce healthcare burden and improve work capacity. However, causal inference is limited and prospective studies are warranted to test whether timely initiation improves long-term clinical and socioeconomic outcomes.

Reference: Ukkola-Vuoti L, Klåvus A, Toppila I, et al. A population-based registry study on psoriasis-associated burden of disease in Finland. Front Med (Lausanne). 2025;12:1605100. doi: 10.3389/fmed.2025.1605100.