A Boy With Blau Syndrome Misdiagnosed as Refractory Kawasaki Disease

Abstract

Blau syndrome is a systemic autoinflammatory disease presenting with non-caseating granulomatous dermatitis, chronic uveitis, and arthritis. It is caused by a gain-of-function variant of the nucleotide-binding oligomerization domain protein 2 gene, which leads to the overactivation of inflammatory cytokines and eventually causes autoinflammation. Since the symptoms of Blau syndrome are nonspecific and usually do not appear simultaneously, it is challenging to differentiate Blau syndrome from other inflammatory disorders. This is a case report of a 13-month-old boy who had suffered from recurrent skin rash and fever. The patient was previously misdiagnosed as refractory Kawasaki disease twice and was treated with intravenous immunoglobulin and systemic glucocorticoid, which only resulted in transient improvement of the symptoms. He was eventually diagnosed with Blau syndrome.