Coal tar is like being tarred (as in tarred and feathered) then baked under UV lights, not exactly appropriate for 3 year olds...
I worked on the Elidel launch, what a great drug until they ran into some issues, still safe but hysteria set it.
Latest that we have our 2 year old on is "Atopiclair"
http://www.atopiclair.com/
Fairly expensive but its "non-steroidal" and has been good for our little one.
The key is nice warm bath and immediate moisturization, the heavier the better, we like Eucerin. Over the patches we spread teh atopiclair then the eucerin over it...
Peds won't write elidel for kids anymore but that stuff was like miracle cure...too bad.
Adam