Blau syndrome, a rare monogenic autoinflammatory disease resulting from mutations of the NOD2/CARD15 gene on chromosome 16, is classically characterized by a clinical triad of granulomatous polyarthritis, uveitis, and skin involvement with an onset in early childhood. Skin manifestations are generally the first sign of the clinical Blau syndrome triad. Recognition of typical joint manifestations in children may aid in the differentiation between Blau syndrome and “classical” sarcoidosis.