Although clinical assessment has historically been the primary method used for pediatric localized sclerosis (LS) diagnosis and staging, highfrequency ultrasonography (HFUS) is being investigated as a more accurate evaluation method for lesion. This study aimed to assess, compare dermal and subcutaneous tissue characteristics and enhance enhance lesion staging in pediatric LS patients using HFUS. Twenty two LS patients were cross-sectionally evaluated with B-mode ultrasonography. Lesions were clinically staged, and dermal and subcutaneous tissue characteristics were compared with healthy tissue using HFUS. Among 55 lesions, 27 were active/new (49.1%), and 28 were atrophic/old (50.9%). Active lesions typically had increased dermal thickness in 66.6% of cases, while atrophic lesions often showed decreased dermal thickness (78.5%), with significant differences (p<0.05). Dermal echogenicity decreased in 40.7% of active lesions but remained largely unchanged in atrophic lesions (82.1%) (p<0.05). Subcutaneous tissue thickness significantly decreased in atrophic lesions (78.5%) and increased in 59.2% of active lesions, with a significant difference (p = 0.002). Subcutaneous tissue echogenicity increased in 44.4% of active lesions and remained mostly unchanged in atrophic lesions (67.8%). Importantly, a considerable proportion of lesions diagnosed as active through physical examination were actually inactive on HFUS evaluation (55.6%), while a significant portion of lesions categorized as atrophic on physical examination displayed areas of inactivity upon ultrasonographic assessment (35.7%). These findings highlight HFUS's potential as a valuable diagnostic tool and reveal discordances between clinical and HFUS staging. Ultrasonography offers an objective LS lesion evaluation, especially in pediatrics.