Neuro-Sweet syndrome - a rare differential diagnosis in aseptic meningoencephalitis

Acute febrile neutrophilic dermatosis (Sweet's syndrome) is a dermatological entity, which may be associated with malignancies, drugs, and infections and which is characterized by high fever, elevated neutrophils, and tender erythematous skin lesions. Involvement of the nervous system - Neuro-Sweet syndrome (NSS) - is rare, manifesting most commonly with an encephalitic syndrome in addition to fever and dermal lesions. Here, we report an unusual case of NSS in a Caucasian male patient in the setting of B-cell-lymphocytosis, with encephalitis preceding dermal lesions. Symptoms resolved completely in response to corticoids. NSS is a rare, but important differential diagnosis in the work-up of febrile aseptic meningoencephalitis unresponsive to anti-infectious treatment. Due to its rarity and clinical variability, diagnosis of NSS might be challenging. Knowledge of this entity may facilitate proper diagnosis and differentiation from conditions with similar clinical presentation, especially Neuro-Behçet's disease. It may further lead to early detection of a potentially underlying malignancy and help in initiating adequate therapy.