Purpose To explore epidemiological data of pediatric psoriasis age under 18 years old regarding, types of psoriasis, the correlation with metabolic syndrome (MetS), treatments, and treatment outcomes of at least one year follow-up. Patients and Methods This was a 20-year-retrospective study of pediatric psoriasis patients in a single tertiary pediatric referral center, Faculty of Medicine, Khon Kaen University, Thailand, between January 2001 and December 2020. The diagnosis of psoriasis was based on recorded diagnosis from ICD-10, and medical record was evaluated by certified pediatricians. Results There were 177 pediatric psoriasis in the study population. The mean age was 10.50, SD 4.80. The mean body mass index (BMI) was 19.10 (SD 5.44). There were 52 cases (29.37%) with MetS. Pediatric psoriasis patients over the age of 12 years old developed MetS 27 out of 70 cases (0.38) compared to the patients younger than 12 years old (25 out of 107 cases, 0.23), absolute risk reduction = 0.15, 95% CI 0.01–0.29, P = 0.029. The overall outcomes of pediatric psoriasis were good even though traditional topical and systemic treatments were provided in the study population. Conclusion The present study revealed that there was 15% increased MetS in the pediatric psoriasis patients over the age of 12 years old as compared to the patients of prepubertal age (≤12 years old). Increased attention to the early detection of MetS in pediatric psoriasis is recommended. Biologic therapy would be an alternative option in severe recalcitrant pediatric psoriasis cases in the future.