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.