Evaluation Of Stress, IL-18, And IL-22 Levels And Their Interrelationships In Patients With Seborrheic Dermatitis

Introduction: Seborrheic dermatitis (SD) is a chronic inflammatory dermatosis with multifactorial pathogenesis. Cytokines such as IL-18 and IL-22 are implicated in inflammatory and stress-related pathways, but their roles in SD remain unclear. Objectives: To investigate serum IL-18 and IL-22 levels in SD patients, evaluate their relationship with disease severity and perceived stress, and explore their potential relevance to SD pathophysiology. Methods: In this cross-sectional study, 46 SD patients and 42 healthy controls were included. Disease severity was assessed using the Seborrheic Dermatitis Area Severity Index, and stress with the Perceived Stress Scale-10. Serum cytokine levels were measured by ELISA. Group comparisons and correlation analyses between cytokines, disease severity, and stress were performed. Results: Patients had significantly higher stress scores than controls (mean 19.8 ± 4.6 vs 13.7 ± 4.2). Serum IL-22 levels were elevated in SD (median 369.3 vs 143.1 pg/mL; P<0.001). A cutoff of 202.8 pg/mL for IL-22 distinguished patients from controls, with 100% sensitivity and 97.6% specificity. IL-18 levels did not differ significantly between groups. IL-18 and IL-22 showed a moderate negative correlation (r=−0.409; P=0.005). Stress scores correlated positively with disease severity (r=0.336; P=0.022), and IL-22 correlated with stress across all participants (r=0.541; P<0.001). Conclusions: Elevated serum IL-22 levels observed in patients with SD suggest a possible involvement of IL-22 in SD-related inflammatory processes. The observed associations between IL-22 and perceived stress support a potential interaction between immunological and psychosocial factors in SD. These findings should be considered exploratory and warrant confirmation in larger studies.