A case of seronegative primary Sjögren's syndrome complicated by Takayasu arteritis in a Japanese girl.

In paediatric primary Sjögren's syndrome (SS), the initial symptoms manifest systemically, such as fever, general fatigue, and lymphadenopathy, rather than sicca symptoms. Most children with primary SS have autoantibodies, such as antinuclear, anti-Ro/SS-A, and/or anti-La/SS-B antibodies; however, some patients are seronegative. Similar to paediatric patients with primary SS, those with Takayasu arteritis (TAK) initially only present constitutional symptoms, making it difficult to suspect, unless characteristic features are present. To our knowledge, there have been no reports of the coexistence of both diseases in children. We present a rare case of seronegative SS complicated by TAK in a 9-year-old girl who presented with a persistent low-grade fever, general fatigue, cervical lymphadenopathy, and multiple caries. Although blood examination revealed all autoantibodies to be negative, a lip biopsy revealed lymphocytic sialadenitis, and a sialoscintigraphy indicated hypofunctional salivary glands, leading to the diagnosis of seronegative SS. The patient was treated with low-dose glucocorticoid and immunosuppressant administration to inhibit persistent inflammation and the progression of salivary gland dysfunction; although the symptoms resolved, inflammatory markers remained elevated. When the patient was 14 years old, cervical bruits were incidentally found, and TAK was suspected based on cervical ultrasonography and magnetic resonance angiography findings. 18F-fluorodeoxyglucose-positron emission tomography/computed tomography results demonstrated increased fluorodeoxyglucose accumulation from the ascending to descending aorta. Therefore, she was diagnosed with SS complicated by TAK, which is rare. Aortitis should be suspected when the cause of persistent inflammation cannot be ascertained in patients with SS.