Seasonal Variation of Psoriasis and Its Impact in the Therapeutic Management: A Retrospective Study on Chinese Patients

BACKGROUND: The seasonal patterns of psoriasis have been observed in previous studies. However, no published data indicated the risk factors associated with the seasonal variation. PURPOSE: This study aimed to investigate potentially related factors associated with seasonal pattern of psoriasis and provide possible implications for alleviating psoriasis in clinical practice. PATIENTS AND METHODS: The retrospective study was conducted in Chinese patients with psoriasis. Demographic and clinical information were collected. Multivariable logistic regression analyses (calculating adjusted odds ratios [AORs]) were used to analyze data. RESULTS: We continually enrolled 2270 patients (1496 males and 774 females) with psoriasis based on inclusion criteria. Disease duration (AOR=1.06, 95% CI: 1.05–1.07), hyperlipidemia (AOR=1.77, 95% CI: 1.06–2.98) and smoking (AOR=1.40, 95% CI: 1.17–1.68) were significantly associated with severe psoriasis in autumn/winter. Age (AOR=0.98, 95% CI:0.97–0.99) and occupations with more sunlight exposure (AOR=0.78, 95% CI: 0.61–0.99) were negatively associated with the seasonal aggravation. Subgroup analysis showed that occupations with more sunlight exposure (AOR=0.64, 95% CI: 0.43–0.94) were protective factors only in late-onset psoriasis but not early-onset, while smoking (AOR=1.39, 95% CI: 1.11–1.74) was risk factor in the early-onset psoriasis. CONCLUSION: Psoriatic patients who had occupation with more sunlight exposure were less likely to report aggravation of psoriasis in autumn/winter. On the contrary, smoking and hyperlipidemia were positively associated with the seasonal aggravation. Additional prospective study is needed to identify the causality.