To describe a case of centrally disseminated nocardiosis associated with dupilumab therapy.

Nocardia is a gram-positive rod typically found in soil. Infection is most common in immunocompromised individuals and carries high risk of morbidity and mortality due to its nature to disseminate from the skin to the lungs and nervous system. Central nervous system involvement can cause encephalitis and abscess formation. Dupilumab, a monoclonal antibody that blocks IL-4 and IL-13 signaling, is FDA-approved for atopic dermatitis and asthma. Though not formally considered an immunosuppressant, the medication targets pathways important for antibody and cell-mediated immunity.

A 63-year-old woman with eczema, type 2 diabetes, hyperlipidemia, and prior Stevens-Johson syndrome from trimethoprim-sulfamethoxazole use presented with fevers and erythematous thigh lesions after abrading her knee while gardening. Dermatology diagnosed her with cellulitis, and she received five days of linezolid. After initial improvement, she developed nausea and headache, which were attributed to antibiotic side effects. A few days later, she had an episode of syncope associated with 104°F fever, prompting readmission. Blood cultures grew Nocardia farcinica. Brain MRI revealed multiple ring-enhancing lesions within the bilateral cerebral hemispheres, cerebellum, and brainstem compatible with brain abscesses. She was started on imipenem and linezolid; imipenem was later discontinued due to resistance.

Three months later, she developed right-sided facial numbness and gait instability. Neurosurgery recommended intrathecal amikacin. Despite this, her neurological status progressively worsened, with enlarging abscesses identified on follow-up MRI.

Nocardia is a common bacterium that infrequently causes disseminated infection in the immunocompetent. Early identification and aggressive therapy are critical given the rapid progression of nocardiosis. This case raises concerns about potential infectious complications of the IL-4 receptor blocker dupilumab, despite its designation as a non-immunosuppressant.