CSF rhinorrhea refers to a fistula between the subarachnoid space and nasopharynx. It was first described by Galen in 200 BC and Dandy was the first to successfully close one using frontal craniotomy in 1926. CSF rhinorrhea can be caused by congenital defects, trauma, surgery, or idiopathic factors and is diagnosed using clinical tests and imaging like MR cisternography. Treatment involves conservative management or surgical repair via endoscopic or open craniotomy approaches depending on the location and cause of the leak.