Scleromyxoedema is a rare skin disease, characterized by deposition of acid mucopolysaccharides in the dermis. Although the disease primarily affects the skin, cardiovascular, renal and rheumatological manifestations have been described. In addition to these noncutaneous manifestations, about 15% of patients have central neurological symptoms such as psychosis, convulsions and encephalopathy. Successful therapy is difficult but high-dose intravenous immunoglobulin (IVIg) has been reported to be a successful treatment. We describe a patient with scleromyxoedema who presented with novel central nervous system manifestations of chronic cognitive impairment and dementia (Folstein Mini Mental State test score 8/30), which improved within a week after treatment with high-dose IVIg, with full restoration (Folstein Mini Mental State test score 27/30) at 2 months.