Background: Psoriasis is a skin disease affecting 2.3% of the Iraqi population and begins as a local disease with subsequent systemic comorbidities. Aim: The aim was to clarify whether psoriasis is a local or systemic disease. Materials and Methods: A total of 211 subjects with psoriasis and 163 sex- and age-matched controls were included in the study. Serum adiponectin, interleukin-6, interleukin-8, interleukin-10 (IL-10), interleukin-23 (IL-23), interleukin-18 (IL-18), paraoxonase, lipoprotein (a), osteopontin, chemerin, tumor necrosis factor-a (TNF-a), high-sensitivity C- reactive protein (hs-CRP), bilirubin, D-dimer, and creatinine were determined using commercial kits. Results: There was no significant difference in the mean age and BMI between psoriasis and the control groups. However, there was significantly higher mean serum values of IL-6, IL-8, IL-10, IL-23, lipoprotein (a), chemerin, TNF-a, hs-CRP, osteopontin, D-dimer, troponin I, creatinine, bilirubin, and platelet counts in psoriatic patients than in the controls. Meanwhile, the serum mean values of adiponectin, paraoxonase, and cortisol were significantly lower in psoriasis subjects than in the controls. The mathematical model was proposed to clarify whether psoriasis is a systemic or local disease. The application of the model to our data of biomarkers indicated the presence of systemic inflammation in psoriasis. Conclusion: The present study finding suggests that psoriasis is a systemic disease rather than a local skin disease. However, there is a need for the application of the model in a large-scale study.
