A bulging fontanel in an infant is generally regarded as a sign of serious central nervous system disease. It may be caused by meningitis, hydrocephalus, cerebral hemorrhage, brain abscess, or tumor. Benign intracranial hypertension, a syndrome of increased intracranial pressure with a normal ventricular system and a cerebrospinal fluid of normal composition, also will produce a bulging fontanel. Hypoparathyroidism,1hypovitaminosis A,2,3hypervitaminosis A,4hypophosphatasia,5marked anemia,6chlortetracycline therapy,7Addison's disease,8and pulmonary emphysema,9have been reported as causes of benign intracranial hypertension. Scattered reports10,11,12of the association of roseola infantum with a bulging fontanel have appeared in the literature. The following report of 2 cases is being presented as further illustration of this disease as a cause of benign intracranial hypertension. Case1.—A 5-month-old white boy was in good health until 3 days prior to admission, when the mother noted that