Listeria monocytogenes Meningitis With Hydrocephalus in a Patient With Sjögren's Syndrome and Penicillin Allergy.

Listeria monocytogenes is an opportunistic Gram-positive intracellular pathogen that predominantly affects elderly and immunocompromised individuals. Central nervous system involvement may result in meningitis or meningoencephalitis, with hydrocephalus representing a rare but serious complication associated with high morbidity and mortality. This case report describes a 62-year-old woman with Sjögren's syndrome on methotrexate who presented with fever, headache, and altered mental status. Imaging revealed communicating hydrocephalus, and CSF analysis confirmed Listeria monocytogenes meningitis via multiplex PCR. Management was complicated by penicillin allergy and subsequent hypersensitivity to trimethoprim-sulfamethoxazole, eventually requiring a transition to oral linezolid. Targeted therapy led to the resolution of hydrocephalus and significant neurological recovery by discharge. This case highlights the importance of considering Listeria in immunocompromised patients and the necessity of alternative antimicrobial strategies when faced with rare complications and complex drug allergies.