LAUSR

Chronic lymphocytic thyroiditis (CLT), also known as Hashimoto's thyroiditis (HT) or autoimmune thyroiditis (AIT), is a T cell-mediated organ-specific autoimmune thyroid disease. It is a common etiology of acquired thyroid dysfunction in pediatrics. In HT, early adolescence is a period of high risk of diagnosis. Henoch-Schönlein purpura (HSP) is the most common primary systemic vasculitis in pediatrics, with small vasculitis as the main lesion. We described a rare case in which a pair of twin sisters were diagnosed with Hashimoto's thyroiditis and allergic purpura. A pair of twin sisters were found to have skin ecchymosis and protruding eyes when they were 8 years old. We aim to provide clues to the pathogenesis of Hashimoto's thyroiditis and allergic purpura disease.