Infliximab-Induced Aseptic Meningitis during the Treatment of Psoriatic Arthritis

A 42-year-old Japanese man presented with persistent headache during treatment for psoriatic arthritis (PsA) with infliximab. Treatment with infliximab was initiated 3 years before and the psoriatic skin lesions with arthritis were well controlled. However, after 21 doses of infliximab, the skin lesions and joint pain exacerbated and became intractable. Ten days after the dosage of infliximab was increased, the patient experienced headache and nausea with high fever. He had scaly, well-circumscribed erythemas on his trunk, extremities, and deformed nails. He also had swelling and pain in multiple joints. His complete blood and differential leukocyte counts were normal. The level of C-reactive protein was 16.66 mg/dL, whereas anti-infliximab antibodies were absent. Nuchal rigidity was absent and there were no abnormal neurological findings; however, jolt test results were positive. Results from magnetic resonance imaging were normal, whereas those from cerebrospinal fluid (CSF) examination were almost normal. The CSF contained mononuclear cells and was negative for bacteriological cultures, India ink staining, and polymerase chain reaction amplification of herpesvirus group DNA. Headache and nausea improved 2 months after infliximab was discontinued. The patient failed to respond to infliximab treatment for PsA, and we diagnosed infliximab-induced aseptic meningitis. Infliximab was discontinued and treatment with ustekinumab and methotrexate was initiated. Thereafter, the psoriatic skin lesion and joint pain gradually improved. Infliximab-induced aseptic meningitis may be a differential diagnosis when symptoms of meningitis develop during infliximab administration.