This report presents a rare case of viral encephalitis resulting from co-infection with human herpesvirus 7 (HHV-7) and Epstein-Barr virus (EBV) in a 16-year-old patient with Crohn’s disease following adalimumab therapy. The patient was treated with adalimumab, with an initial subcutaneous dose of 160 mg, followed by 80 mg at week 2, and maintenance doses of 40 mg every two weeks,  three months after initiating treatment, the patient developed symptoms including headache, diplopia, and signs of intracranial hypertension. Metagenomic sequencing of the cerebrospinal fluid identified HHV-7 and EBV as the causative pathogens, with cranial magnetic resonance imaging supporting the diagnosis of viral encephalitis. Targeted antiviral therapy and supportive care led to significant resolution of neurological symptoms. Using the Naranjo’s Assessment Scale, the association between adalimumab and viral encephalitis was evaluated, yielding a score of 5, indicating a "probable" causal link. This case underscores the importance of vigilant monitoring for rare central nervous system viral infections in patients with Crohn’s disease receiving tumor necrosis factor inhibitors.

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