Benign external hydrocephalus (BEH)

What it is

Benign external hydrocephalus (BEH) is a usually self-limited condition in infants, characterized by an increased amount of cerebrospinal fluid in the spaces around the brain (the subarachnoid spaces) and a larger-than-average head. It is generally benign.

Understanding Benign external hydrocephalus (BEH)

In BEH, the fluid spaces over the front of the brain are widened, typically without raised pressure or significant symptoms, and the condition usually improves on its own as the child grows (often by around age two). It is associated with a large head, and there may be a family history of large heads. Many children with BEH develop normally, though some may have mild, transient delays in early motor milestones that typically resolve. Doctors monitor head circumference and development and use imaging to distinguish BEH from conditions that need treatment, providing reassurance while monitoring continues.

Why it matters

Understanding benign external hydrocephalus helps families see that extra fluid around the brain in infancy is often benign and self-resolving, distinct from internal hydrocephalus that may need treatment — which can be reassuring while monitoring continues.