What Causes Dark Itchy Patches On The Palms?

I am 38 years old lady with height 5 feet and weight 70 kgs. I have dark itchy patches on my palms. These started during my pregnancy and are persisting since last 5 years. Doctors called it allergic dermatitis and some called it Eczema. I have been using allopathy medicines, topical applications for some time. I have also tried homeopathy. But the relief is only temporary and the problem is recurring. Please advise if there is any permanent cure for my problem