A 10-year-old boy with Henoch-Schönlein purpura complicated by encephalopathy, transient cortical blindness, and a secondary generalized seizure is reported. Reversible changes in the posterior white and gray matter were seen on magnetic resonance imaging. Our patient illustrates uncommon neurologic manifestations of Henoch-Schönlein purpura. The nature and location of the lesions and the normalization of the patient’s magnetic resonance imaging is consistent with a posterior predominant parieto-occipital encephalopathy and suggests that cerebral edema from blood-brain barrier breakdown may play a central role in the pathophysiology of the central nervous system symptomatology in some patients.