[Successful treatment of a case of steroid-dependent neuro-Sweet disease with dapsone]

A 35-year-old Japanese man was admitted to our hospital with recurrent meningoencephalitis of unknown etiology. He presented with fever, convulsions and loss of consciousness, which started at age 33. We diagnosed him with neuro-Sweet disease (NSD) based on human leukocyte antigen (HLA) B-54/Cwl positivity and neutrophilic infiltration into the dermis in a biopsied skin plaque. Intravenous methylprednisolone and oral prednisolone markedly improved his fever and CSF pleocytosis. Five years later he was again admitted to our hospital with high fever, oral aphthae and dull-red edematous plaques on the face and body. He was conscious, but he had neck stiffness, mild hyperreflexia in all limbs and an extensor plantar response. Laboratory tests revealed increased white blood cell, erythrocyte sedimentation rate (ESR) and C-reactive protein level. CSF analysis indicated mild pleocytosis. A skin biopsy from an edematous plaque revealed neurotrophils infiltrating the upper dermis. We treated him with intravenous methylprednisolone (1 g/day) for 3 days, followed by oral prednisolone (50 mg/day). His symptoms improved remarkably; however, he had recurrence of symptoms, such as fever, meningial irritation and oral aphtae, with attempted taper of prednisolone. We started treatment with dapsone (75 mg/day) in addition to prednisolone, and could taper oral prednisolone, without a relapse. However, because some mildly recurred with the tapering of dapson, we maintained dapsone treatment at 75 mg daily, added colchicine (1 mg/ day) and tapered only prednisolone. His symptoms were improved and no relapse has been observed. NSD is characterized by neurotrophic hyperactivation and infiltration of tissues. It is highly responsive to systemic corticosteroid therapy; however, some cases show frequent recurrences on tapering of corticosteroids. Dapsone is considered to prevent neurotrophic overactivity. In this case, dapsone was supposed to be effective to prevent reccurence of NSD upon tappering corticosteroids. Dapsone should be a therapeutic options for steroid-dependent NSD showing frequent recurrence.