Severe Diffuse Takayasu Arteritis Manifestation in Childhood.

backgroundTakayasu arteritis (TA) is a large-vessel vasculitis that primarily affects the aorta and the pulmonary and coronary arteries. CASE SUMMARY: A 4-year-old boy was diagnosed in 2022 with pyoderma gangrenosum (PG) and required prolonged multidisciplinary care, including aggressive medical immunosuppression for severe skin lesions. In October 2024, after a period of clinical stability, he presented with a seizure and right-sided weakness. Head and neck computed tomography angiography revealed features of acute inflammatory vasculitis. These findings along with clinical criteria led to a diagnosis of TA. Vascular imaging (echocardiogram, computed tomography, magnetic resonance imaging) showed diffuse disease affecting the aortic root, aortic arch, proximal supra-aortic vessels, proximal descending aorta, and proximal left pulmonary artery. The patient's immunomodulatory treatment was switched to a combination of corticosteroids, cyclophosphamide, and antiplatelet therapy, with ongoing careful multidisciplinary clinical surveillance and assessment of treatment efficacy. DISCUSSION: This case highlights the rare coexistence of PG and childhood TA, with only 10 cases reported in the literature. Despite extensive immunosuppressive treatment for PG, the patient exhibited severe, diffuse vasculitis.