Skin symptoms during the pollen seasons and their association with the severity of seasonal allergic rhinitis in Yamanashi, Japan

Background During the Japanese cedar pollen (JCP) and cypress pollen seasons, skin symptoms are occasionally reported in individuals with seasonal allergic rhinitis (sAR). Although the seasonal worsening of atopic dermatitis is known, the clinical relevance of pollen season skin symptoms in the broader population with sAR remains unclear. This study examined skin symptoms during the pollen seasons and their association with severe sAR. Methods This cross-sectional study included 4119 patients with sAR during the JCP and Japanese cypress dispersal seasons, who were categorized based on skin symptom presence or absence. The primary outcome was severe sAR. Multivariable logistic regression analyses using inverse probability weighting were performed to evaluate the association between skin-related variables and severe sAR. Additional analyses were conducted, with adjustment for skin symptom scores. Results Skin symptoms were reported by 1993 (48.4%) patients, of whom 985 (49.4%) experienced seasonal worsening during the pollen seasons. Facial and extremity or trunk involvement was observed in 64.8% and 56.2%, respectively. In inverse probability weighting-adjusted analyses, skin symptom seasonal worsening (OR: 1.45, 95% CI: 1.14–1.86), facial involvement (OR: 1.47, 95% CI: 1.12–1.93), and moderate-to-most severe skin symptoms (OR: 1.35, 95% CI: 1.02–1.79) were associated with severe sAR. These associations were not materially altered after additional adjustment for skin symptom scores. Conclusions Approximately one quarter of patients with sAR reported seasonal worsening of skin symptoms during the pollen seasons. These findings suggest that skin symptoms are associated with increased sAR severity and may reflect interactions between cutaneous and airway inflammation.