What Causes Clotty Blood Discharge From Nose While Having Allergies?

My daughter has allergies and has nose bleeds often but last night and today she has had a new concerning type of nose bleed. A few times last night and a few times today, thick clotty (as described in another question) blood come out of her nose as though it were a bunch of mucus when someone has a cold, but in the form of blood. The amount of thick blood was substantial (similar to the volume of a small marble) for each nose bleed and the thickness worried me more than anything. What does this indicate?