I was in the same boat as you... had bad eczema and dermatitis as a child and psoriasis all my adult life but during pregnancy and after, the eczema flared up a lot on my hands and feet. I occasionally use Diprosone too but I avoided it while pregnant and BF because if memory serves it is a corticosteroid.

Dr Gillian McKeith (renowned dietician from the UK) says that eczema often manifests itself for the first time in motherhood. She recommends generally (ie, not for pregnancy) the following nutritional supplements: Vit B complex, Vit E, Biotin, Zinc, and essential fatty acids such as flax or evening primrose oil. I would think any good vitamin supplement made for pregnancy would have the safe limits of each of these so maybe get onto taking these if you aren't already?

She also suggests application of flax, evening primrose and/ or Vitamin E oil directly on your skin, as well as calendula cream. Since DD was born I began using Eulactol cream for very dry skin (it's Vitamin E enriched) and Invite Vitamin E oil or flax oil and the combination works really well to get rid of it. I vaguely recall reading that Vitamin E may not be safe to apply topically during some stages of pregnancy so please check that out for yourself before using it. If you are wary maybe a safe for pregnancy intensive moisturiser (eg, Mustela) might be the go? Swisse odourless fish oil is good too if your stomach is still sensitive.

Best of luck with it.