Prevalence and risk factors of papular urticaria among school children in Cartagena, Colombia.

Introduction: Papular urticaria (PU) is a chronic allergic reaction to arthropod bites and is a common cause of pediatric dermatologic consultations in tropical regions. This study aimed to assess the prevalence and associated factors of PU among children in Cartagena, Colombia, and to explore the relationship between insect presence and disease presentation. Methods: Surveys were used to assess living conditions, and the diagnosis was confirmed by medical history and physical examination. Results: A total of 725 children aged 1-6 years from 30 schools and 13 childcare centers were included, PU was diagnosed in 260 children, resulting in an age- and gender-adjusted prevalence rate of 35.9% (95% CI: 30.3-43.4). Lesions were primarily found on exposed areas, such as the lower limbs (97%) and arms (54%). Children aged 1-2 years (aOR = 3.01, 95% CI: 1.54-5.93, p < 0.001) and 3-4 years (aOR = 1.84, 95% CI: 1.11-3.08, p = 0.02) had a higher risk of PU than those aged 5-6 years. The antecedent of mosquito bites was reported in most PU cases (96.0%) and controls (93.0%), without significant differences between groups. The frequency of mosquito presence at home was similar between case and controls. Mosquito density was higher in the lower socioeconomic strata (p < 0.001). The most commonly identified species were Conclusion: We identified a high prevalence of PU in the city. Despite the widespread presence of mosquitoes, no association between mosquito bites and PU was observed. Younger age emerged as a risk factor for PU, and socioeconomic disparities influenced higher mosquito density.