Hi Vanessa,
I'm sorry to hear you and your son are having a hard time this summer! It seems to be the same everywhere, even here in Prague, Czech Republic. This summer season is turning into a hard one for asthmatics and people who have allergies.
Your son sure sounds as if he could have asthma and/or allergies. It's hard when you know what is going on with your son, but there are no symptoms when your son sees the doctor. You might ask the doctor if he could prescribe an emergency inhaler and antihistamines and see what he says. It might also help if you keep an asthma/allergy journal of your son's symptoms. Keep track of the dates, times, places, and symptoms your son is having, along with what you believe might have triggered the symptoms. This can be a very important tool in helping your doctor to see exactly what is happening when your son has an allergy/asthma attack.
My daughter had an emergency inhaler from the time she was 8 years old. When she was at school, the school nurse or office personnel kept her inhaler (with her name on it and instructions on how to use it) in the school office. When she would have an attack, she would go straight to the office where they would give her the inhaler and monitor her.
So, age should not be a factor, and these things can be dealt with at school as long as office personnel understand how to monitor the use of the inhaler and symptoms to watch for. If your doctor does prescribe an inhaler, you should check with your school to see what procedures need to be followed for your son to have an emergency inhaler at school.
Good luck with your son's allergies and asthma! Let us know how it turns out!