"Neuro-sweet disease": benign recurrent encephalitis with neutrophilic dermatosis

To describe benign recurrent encephalitis in a case of Sweet syndrome that also showed clinical features of Behçet disease.

A 37-year-old Japanese man developed relapsing and remitting encephalitis and mucocutaneous symptoms mimicking Behçet disease. Magnetic resonance images showed at least 5 episodes of transient abnormal signal intensity in various cerebral regions over a period of 5 years. A skin biopsy specimen of the cutaneous edematous erythematous plaques revealed neutrophilic dermatitis compatible with Sweet syndrome. HLA typing showed B54, which is frequent in Sweet syndrome but rare in Behçet disease. Oral prednisolone therapy (10-60 mg/d) was remarkably effective for the encephalitis as well as for the mucocutaneous symptoms.

We propose that there is an entity that is like Sweet disease, but with recurrent encephalitis characterized by an association with HLA-B54 and a high responsiveness to corticosteroid therapy, which we have tentatively named neuro-Sweet disease, that is distinct from the classic central nervous system involvement of Behçet disease.