Hi Ellen,   Allergies may trigger a Migraine and now there is evidence that nasal steroid spray can add to the problem. This article: Nasal spray for hay fever may trigger migraine.   We kept a Migraine dairy for our son and learned some of his Migraines are triggered by dehydration, chocolate, and interrupted sleeping patterns. Allergies can trigger a Migraine too, sometimes they do for him.  A free Migraine diary is a great tool to use to track what things in your daily routine may be contributing to your son's Migraine frequeny and severity. You can download that free diary HERE.   I hope this information helps, Nancy