In reply to marsbar:
Also try sudocrem.. Find it in the nappy section. Its full of zinc oxide, which heals the skin. Slather it on and stick a clean sock over the top over night, in the morning you will be amazed.
Excema can be exacerbated by moisture (think very mild trench foot!), so if you have a footwear set up (socks and boots) thats old, has non wicking fibres, or hasnt been cleaned in a while (ie waterproof membrane is no longer letting steam out), your feel may be staying wet and salty for too long.
Anti-bacterial treatments (such as unreactive treatments like silver oxide) cant hurt.
Not a gp but decades of excema.. But now mostly symptom free