toddler allergies

my son is 3 1/2 and has been having some sinus congestion on and off for the last month or two. his pediatrician prescribed him flonase today. i read on flonase own web site that it is only recommended for children four years and older, so i am not sure i should give this medication to him. also, i am wondering if i should have him tested to see what he is allergic to in order to try to help my sons allergies in any other way. i would like to avoid medication if there are any other steps that should be taken before hand. please help.

[lesleyrado]

Not sure about the flonase, but the allergy test is always the best bet.  Had my 8month old tested two weeks ago, found out he stays with sinus problems due to our dog.  Several years ago when my daughter was two, I had her tested for allergies as well,found out she was allergic to all dairy products and all corn products.  Took her off of this for several weeks, her runny nose & constant cough went away, now she is hardly ever sick and can even eat dairy and corn without any problems.