Thanks for using Health Care magic
I would be pleased to answer your questions.
From the description , of brittle nails and cracks on the skin , it is more of a psoriasis
than eczema . If just topical application of creams is not working , other options of treatments include NBUVB .
NBUVB is a light therapy
where you have to attend the Dermatologist
clinic and expose your hands to light three days in a week . Along with the above , application of VitaminD extract( Calcipotriol
) along with High potent steroid
on the areas of scaling will help
Thanks and Take care