Hello and welcome to Ask A Doctor service. I read your query and here is my answer. As you mentioned that she had undergone x-ray, ct scan and scope, which would be normal as you didn t mention anything about their results. Does she have a past history of trauma to head as this may be csf rhinorrhea. Or it may be vasomotor rhinitis or allergic. But mostly look like it is vasomotor or allergic. You need to talk about it with your doctor who can confirm this. And then it can be treated easily. Hope i answered your question, ask more if you need. Thanks