Giant Cell Arteritis Mimicking Temporomandibular Disorder: Diagnostic Value of Temporal Artery Halo Sign.

Giant-cell arteritis (GCA) involving the temporal arteries primarily affects the older adults, with symptoms that include head pain and tenderness. GCA may mimic temporomandibular disorders by causing jaw opening difficulty. Herein, we report an 89-year-old man who presented with jaw fatigue during meals, frontal headache, and low-grade fever. Examination revealed tenderness and dilatation of the right superficial temporal artery, jaw claudication, an elevated C-reactive protein (8.62 mg/dL), and erythrocyte sedimentation rate of 97 mm/h. Magnetic resonance imaging of the brain showed a small acute infarct. Autoimmune serology and blood culture results were negative. Temporal artery ultrasonography demonstrated a halo sign, and the patient met four of the five American College of Rheumatology criteria, confirming GCA. Treatment with prednisolone (0.5 mg/kg) rapidly improved symptoms and laboratory findings; however, sudden bilateral visual loss occurred despite steroid pulse therapy, and vision did not recover. The findings of this case highlight that, in older adult patients, the halo sign may serve as a practical alternative to temporal artery biopsy for establishing GCA diagnosis.