Welcome, Nathan's Momma, from another Nathan's momma!
I have 3 children with ichthyosis. Nathan is my oldest, nearly 9. I know exactly what you mean about the dry desert. The best thing to do is to soak him for a nice long bath - 30m to an hour, then immediate slather him full of a good cream. So many lotions are way too thin and don't penetrate deep enough into the skin and it just dries out again. Most people around here use Aquaphor, which works really well but is really greasy, Eucerin Plus, (these two you can get for free from the company) Jergen's Ultra Healing, Cetaphil, or Aveeno 24 Hour.
The stinging prescription creams are usually because they have acids in them like lactic acid or urea that help eat through the thick skin and help it to come off. I wouldn't use them on my babies, either.
You can get a lot of help if you have a knowledgeable doctor. Most of them are flying by the seat of the pants method and don't have much experience. So often I see people get a diagnosis of ichthyosis, and if it's mild it must be IV, and if it's severe, obviously it's Harlequin! Just yesterday I was talking to someone whose doctor was having trouble determining if they had Netherton's or EHK - one is a skin too thick/blistering problem, the other is a skin too thin/failure to thrive problem.
One thing I want you to do is to check out www.firstskinfoundation.org
and give them a call. They will put you in touch with someone sort of nearby through their ambassador program,and also, take a look at the family conference. The next one is in June 2012 and is in Denver. They have a scholarship available to pay for the hotel and registration fee, so you can go for only the cost of airfare. It's a huge eye-opener and a really good chance to meet some really nice people and make some friends that have the same issues as you. Not to mention, the tips and tricks those of us with older kids have come up with can save you from reinventing the wheel.
I'll PM you as well.