A 19 year old female develops bleeding from the nose during menstruation. What is she most likely suffering from?

Patient in the question is most likely suffering from vicarious menstruation. It is a condition which is occasionally found in adolescent girls in which they develop monthly epistaxis due to the vascular congestion of nasal mucosa, in concordance with menses. Ref: Textbook of Pediatric Emergency Medicine edited by Gary R. Fleisher page 975.