We use tazorac, too. Good stuff, but we're REALLY cautious with it given how the oral steroids cause problems. Especially with a child, I would and do use it as sparingly as possible. The paperwork on it says that what is absorbed takes about 19 hours to clear out of the body, so using it daily could potentially have the same retention/side effect problems. One of my friends with LI had to stop using soriatane due to side effects, switched to Tazorac and now can't take it either becuase the side effects came back.
If it works, use it, just keep in mind the long term potential with it, especially in a young, growing child. For us, we apply it to the neck and armpits once every few months just to clear buildup, and maybe about every 6 weeks on my husband. At that level of exposure, we're not too worried about side effects.
If I were you, I'd call my dermatologist, or if you don't have a good one, pose the question to the FIRST medical advisory board. I'm sure they'd be interested in the MRSA-killing potential of the steroid.
Ichthyosis-en-Confetti Type 2
Husband, Nathan - 10, Elliot - 7, Oliver - 4, all affected.
I also have an unaffected daughter, age 8.
email: jennifer at confettiskin dot com
facebook - find me on "ichthyosis mommy spot" or "friends of ichthyosis"