If you notice a commonality to the allergy, great, you can
avoid those things. You can
even write down everything you
were exposed to, close to the day you got the reaction, and figure it out. And anytime you get a runny nose, you are going to get a headache, so could be a few allergies are at the root of your migraines. Which a very good idea if you tend to get allergic, is to build up your immune system by eating well and so forth, the stuff I recommended earlier.