This is so cheap and easy. I do this for my boyfriend when his eczema is bad.
All you need is a pair of tights or a small mesh sock (you know those little ones that are made out of the same material as tights) and a handful of porridge oats (oatmeal).
Put the oats in the sock and then hook it over the hot tap whilst the bath is running. The bath will be turn a lovely milky colour and be very soothing for itchy, dry, sore skin!
After the bath has finished running you can tie a knot in the end of the sock and then use it as a gooey body rub, it is very soothing on the skin.
You can also add essential oils to make your skin even more happy!