Signs Of Asthma In Children

My 7 year old daughter has always had a terrible cough virus (from about age 2). She has never hissed to my knowledge, and we have always treated for asthma according to the instructions of his Dr's. She was wheezing and low oxygen when she had a chest cold once (heard by the doctor) and she also had pneumonia. When she receives an infection following a virus his cough is worse. It's worse at night. Even with the use Qvar (sometimes for months at a time), she returns with this cough. I also give him Albuterol and she gets a lot of steam baths when she coughs. It was a relief when placed on prednisone and (rare occasions, it was Rx'd) cough syrup cons codiene.
She also constantly battles with eczema.
For years I feel like I could not keep his "asthma" under control, as I did not even want to take drugs that help a lot (I only see some changes when given).
Even with respiratory treatments in the ER. Should not all these things work??? Should she be able to function better with a virus?

So she is sick today and I took her to the Dr. again yesterday and they said his lungs sound good (I used to hear in spite of coughing, until it throws the routine, it goes well). Dr think we have seen that cough is post nasal drip. I read about him and that sounds a bit like what she did. I have been giving him Benadryl (never done that before). Whenever I ask him if his chest hurts she says no ... my throat tickles and she complained of stomach pains (I'm hurt by coughing). Now she says she feels a squiggling his throat. With Benadryl she has done in the night and only coughed several times last night.

Is my child with asthma may not be all asthmatics? Or that asthma is not the main problem?
Perhaps all the symptoms due to a problem post nasal drip?
How its sales Peditrician certainly I am not giving her medication, she may not need?!? I do not want to endanger it, but I always felt that we did not see dramatic results.

When she is well she has no cough or other problems. She got some food allergy to dairy products and eggs, but it's been years since she has been tested for those and even then it was very weak positive. We tested her because she would get hives on his face when eating anything to do with ranch dressing. She never complained after eating milk / cheese, ice cream if she does not like eggs. Mari and I have allergies, but nothing diagnosed, I use a nasal spray when needed. It seems to sneeze (like everyone) at times, but for the most part, do not seem to suffer terrible allergies. My two other children show no signs of anything like that.

Thoughts?

Hello, I have serious sinitus where I regularly get sinus infections and asthma have also fragile and i fight as much as your daughter seems when I get a virus ... The only way to know if the drugs are doing anything is to wait for drugs against asthma show no signs of work right away it usually takes a week or two to show the effects to be honest, if you do not mean that your pump (seal) your wheezing will not really be too affected for some time. When, on things like prednisone, it is a steroid it will help right away, but if she has a virus, it will help him breathe, but can not cure the virus, it must still pass through. Even if she has a runny nose job, she could still have asthma that drip nasal post only worsen asthma symptoms as I have one of those too, I had the op on my sinuses, but still problems with the drip. It sometimes takes a long doc to diagnose these things it took two years to diagnose problems with my sinuses. It can cause stomach ache with a post.