Have either of you gone to specialists? Maybe it is time to switch doctors or see new ones that might have a better insight as to what is going on with them. Sometimes it takes a fresh pair of eyes to finally get somewhere.
One thing I can think of is if your kids have been checked or immunological disorders? That might explain the frequent infections.
Either way, I think it is time to see a specialist if you aren't getting anywhere..
Sunny
The case of my child is almost similar as yours. I haven't found any answers yet. Keep me posted.