Septic arthritis of the temporomandibular joint (TMJ) is an uncommon disease caused by
microbial pathogens through hematogenous infection, local spread, or iatrogenic infection.
As the symptoms have an insidious onset, the early stage of septic arthritis is often confused
with other diseases. A 49-year-old man was referred for increasing preauricular pain,
swelling, and restricted mouth opening. He had been initially diagnosed as having a conventional
temporomandibular joint disorder and trigeminal neuralgia and had been treated
for the same. Imaging studies including panoramic view, lateral tomography, computed
tomography with contrast enhancement, and magnetic resonance imaging were performed.
Erosive bone change with displacement of the involved condyle, diffuse swelling of adjacent
soft tissue, and fluid collection in the joint space were noted. Needle aspiration of the
joint space and bacterial culture confirmed the diagnosis of septic arthritis of the TMJ and
he was treated with antibiotic therapy and surgical drainage. Clinicians should always consider
the diagnosis of septic arthritis of the TMJ in patients with preauricular pain or swelling.