Objective:

Report a Neuro-Sweet disease case to highlight diagnostic challenges and rapid steroid response.

Background:

Sweet syndrome is a rare, non-infectious neutrophilic dermatosis. Neuro-Sweet disease is an even rarer neurological manifestation, often misdiagnosed as viral encephalitis or neuro-Behçet's due to overlapping clinical and radiological features.

Design/Methods:

A 26-year-old woman presented with status epilepticus and altered consciousness. Erosive-crusted plaques were noted on her abdomen and lower extremities. Labs showed leukocytosis with neutrophilia, elevated CRP (166 mg/dL), and increased ESR (66 mm/h). Autoimmune serologies were negative. Brain MRI revealed bilateral T2-FLAIR hyperintensities in medial temporal lobes. Skin biopsy was performed.

Results:

Skin biopsy demonstrated a dense neutrophilic infiltrate in the dermis, confirming Sweet syndrome. Brain MRI revealed bilateral T2-FLAIR hyperintensities in the medial temporal lobes and right external capsule, with restricted diffusion on DWI sequences. CSF analysis showed mild lymphocytic pleocytosis but was negative for HSV PCR and other viral encephalitis panels. Autoimmune serologies (ANA, anti-dsDNA, antiphospholipid antibodies) were negative. The combination of characteristic skin lesions, histopathological findings, and specific neuroimaging features established the diagnosis of Neuro-Sweet disease. Dramatic clinical improvement was observed within 72 hours of initiating high-dose intravenous corticosteroid therapy, with resolution of seizures and significant improvement in consciousness.

Conclusions:

This case underscores that Neuro-Sweet disease is a critical differential diagnosis in acute encephalitis. The presence of characteristic skin lesions is a key diagnostic clue. Systemic corticosteroids are the first-line treatment and lead to rapid clinical improvement, as observed in our patient. Early recognition prevents unnecessary antiviral therapies and delays in appropriate treatment.