This study aimed to analyze the relationship between cutaneous microcirculation reactivity, retinal circulation, macrocirculation function, and specific adhesion molecules in young patients with uncomplicated type 1 diabetes. Fifty-five patients with type 1 diabetes mellitus (T1DM), aged 8 to 18 years, were divided into subgroups based on skin microcirculation reactivity. The cutaneous microcirculatory vessels were considered reactive if post-test PORH coverage increased compared to pre-test coverage. Optical coherence tomography (OCT) was conducted to detect early retinopathic changes. Macrocirculation was described using pulsatility indices (PIs) determined for common carotid (CCA) and peripheral arteries of the upper and lower limbs. The ankle–brachial index was also assessed. There were no significant differences in retinal circulation and macrocirculation between the studied subgroups. However, there were significant differences between the various subgroups concerning the age at onset of diabetes and the sP-selectin levels but not ICAM-1 and sVCAM-1. The sP-selectin differences remained true after adjusting for age at onset. The sP-selectin level was significantly higher in the subgroup of patients with non-reactive cutaneous microcirculation. The results of our study indicate that sP-selectin may be considered as an immunological marker for cutaneous abnormalities, which serve as an early indicator of endothelial dysfunction in young patients with type 1 diabetes in the absence of classical complication.