My daughter is 6 and I finally have found the combination of things that work for her! Her hands are the worst of anything.
First, you are on the right track with the bathing. My ped asked me that first thing! The fewer, the better because you are washing away what little oils they produce. My daughter gets in the bathtub about every 2 days in summer and other nights there is a "sink bath" where she just washes off. I only wash her hair with shampoo once a week.
Also, she has a special bar of soap in her own little soapdish by the sink- it is Cetaphil brand soap (or cleansing bar, I think they call it) for very sensitive skin. Anything else dries her out terribly!
(Actually I remembered about Cetaphil and decided to try ti with her because it was recommended to me for dry skin/eczema years ago by a dermatologist for my own skin!)
The routine is for us to use the Cetaphil lotion at night before bed (hands and feet can get white cotton socks put on to keep in MORE moisture if they are raw- you will see improvement right away. This also works with other things like Vaseline.) Then we lotion her again in the morning before going out, and she has a pump by the sink as well to put on her hands after each washing.
You can buy the Cetaphil at Walmart. They have a generic too, but we use name brand since it is such an important thing and she is SOOOOO sensitive. It is on the bottom shelf with the lotions in the cosmetics section.
I also had to teach her to dry her hands REALLY well after she washed them, because the water was sitting between her fingers and getting sore.
Make sure he is drinking enough too. I have read that by the time you are thirsty, your body is already dehydrating! Another thing you might look into are humidifiers. They make whole house ones and even little cute ones like frog or Thomas the Tank Engine shaped ones. I find this helps her as well AND seems to have the added benefit that she is not as stuffy with allergies.
As far as his scalp, maybe you could rub the Cetaphil lotion into it at night before bed for a few nights when you aren't planning to go anywhere (maybe the weekend) and see if that helps it any, and then wash with the Cetaphil soap OR get a presciption shampoo even from the ped?
(The Cetaphil is about $8/big bottle for the lotion at Walmart, but we got ours back in November and it's still pretty full, so it goes a long way! Ours had a sample soap attached too and she's still using that one.)
We got to Thida Maw in Algonquin for our ped. She specializes in allergies as well, but I agree that you may want to make a dermatologist appt.
Organic sites or stores like Whole Foods may have products like shampoo that would be better and less drying too.
Hope this helps!!
'M.