Background: Atopic dermatitis is a chronic, relapsing inflammatory skin disorder in which immune dysregulation and skin barrier dysfunction play crucial roles, alongside neuroendocrine factors. Psychological stress influences the activity of the hypothalamic-pituitary-adrenal (HPA) axis, thereby altering cortisol secretion and inflammatory responses. However, the relationships among cortisol levels, neutrophil-to-lymphocyte ratio (NLR), psychological parameters, and disease severity remain insufficiently explored. Aim: To compare cortisol levels, neutrophil-to-lymphocyte ratio, and psychological parameters between adults with atopic dermatitis and healthy controls. Materials and Methods: A case-control study was conducted including 12 patients with atopic dermatitis and 12 healthy controls. Serum cortisol levels and complete blood counts (for NLR calculation) were assessed. Psychological status was evaluated using the Patient Health Questionnaire-9 (PHQ-9) and Generalized Anxiety Disorder-7 (GAD-7). Disease severity was measured using the SCORAD index. Statistical analyses included group comparisons and correlation analyses. Results: Cortisol levels in the atopic dermatitis group were significantly lower than those in the control group (p<0.001). Cortisol levels showed a significant negative correlation with SCORAD scores (r = -0.65, p = 0.021) and GAD-7 scores (r=-0.56, p=0.036). A negative correlation was also observed between disease duration and cortisol levels (r=-0.53, p=0.075), although this did not reach statistical significance. Conclusion Dysregulation of the HPA axis in atopic dermatitis, reflected by reduced cortisol levels, may be associated with increased disease severity and psychological stress. These findings highlight the importance of incorporating psychological assessment into the comprehensive management of atopic dermatitis.