My daughter who is now 9 was on Pulmicort very early in her life. Before she was even 2.5 we had to have her tested for cystic fibrosis - she was that bad. She went from 95th%ile in weight to 50th%ile in a month. She did not have CF which was a relief but then we had to decide how to care for her asthma which was like your daughter's - the wheezing would start after a cold. What we really noticed was that she could handle a cold just fine especially if we gave her some decongestants right away to keep everything open (I know you can't give it to children under four anymore but you could 7 years ago). But if she got around cigarette smoke or some other trigger, she would start wheezing. Her triggers were cigarette smoke, humidity (which is hard to get away from in VA), mold and DUST (practically impossible to avoid though this was a mild trigger). She did not have problems with animal dander, smoke from our wood stove...it was weird.
We started going to a pediatric pulminologist and decided on pulmicort and began at regular intervals right away. We did not experience any of the negative side effects. We were careful to rinse her mouth out - if we weren't near water, I would take a wipe/washcloth and wipe her mouth out. We had to mix it with albuterol when she was having an "attack" and for a while with saline. It seemed so complicated and tiresome but it was worth it. She has been symptom free for over 2 years and has not been on daily meds for even longer than that. We keep albuterol inhalers around just in case but we think the worst is over. She will always have to be careful but it worked for us.
You want to treat daily, rather than just the episodes for several reasons. The most obvious is it will prevent an episode whenever it should just pop up. Another reason is if she is having several attacks and the lungs haven't healed properly, this will help her continue to breath free and easy - it helps keep the lungs open. If something does get in and she has another episode, then her lungs are already used to the pulmicort and it can work that much more efficiently. It all depends on how often she wheezes and how bad it is. Every 4 months isn't enough time for her lungs to heal before it happens again. You need a year between lung episodes. They are just so moist and full of mucus to begin with. The risks are permanent lung damage that may not show for a few years or such weakened lung function that she will always need something.
My daughter was never hospitalized, thank God, and only had 4 really bad episodes but they came one right after another, four months in a row. We didn't know if it were going to be an habitual thing so we felt we needed to stop it rather than wait to find out. And the onset was sudden. She would be taking a nap breathing fine. I would look again and she would be panting as if she had been running a marathon. And it would look like she had a hole in her chest where she would suck air in so hard.
My best advice - keep her as healthy and as active as you can now. Keep her lungs strong, keep her away from any triggers, keep her away from other sick kids if possible, keep her active to make the lungs work hard. I was told that sometimes these things come back in the teenage years, the 20's etc. so always keep an eye on her even when it looks like she has grown out of it. Then as she ages and the normal lung function diminishes (which happens to all of us) she won't have extra issues with scarring, etc.
I hope this isn't too long!! This is a real personal issue with me and I really hope I helped you. I agree that you should look at all the possible causes before you make your final decision and also try some natural remedies. Keep her as healthy as you can since the lungs are slow to heal and repeated "attacks" really weaken them. I am in to natural remedies myself and highly recommend trying to let the body heal itself but when all else fails (if it should) then at least try the pulmicort.
Good luck and God bless,
Z.