Hi J.,
My son and I both have terrible seasonal allergies. He is 7 and has had them since shortly after he was born. He has asthma associated with them as well. He takes claritin (OTC)only when needed and Singulair daily, which helps with the allergies and to prevent asthma flare ups. He takes Advair as well, but that is a preventative med for the asthma. We went to an EENT doctor who specializes in seasonal allergies here in Carrollton (Dr. David Chihal). He had us do RAST tests to find out specifically what we are allergic to. (We had blood drawn and sent to a lab.)
Then Dr. Chihal used that information to make our personalized allergy shots. My basic understanding is that allergy shots desensitize your immune system to the things you are allergic to. I have to say that since starting allergy shots (about a year ago) both of us take less over the counter medicine even during the times of year when the pollens that we are allergic to are high.
You might investigate allergy shots if your son has these kinds of allergies, and you think he could tolerate weekly shots. For us it has been a more effective and cheaper long term solution than being sick all the time and spending lots of money on medicines that were only covering up symptoms.
S.