Is Prednisone Recommended To Cure Itching Caused By Dermatitis?

My wife has had very itch skin most notably in the neck line, on her wrists and most recently behind the golds of both knees as well as on her arms. Yet his has been on going for another two months. She has been to dermatologist twice and received oral prednisone and topical. Not much help. Dx was contact dermatitis. However, still very itchy. Rec getting a scraping to help find out the cause? Wife very fit and healthy, with Jo recent dietary changes, nor working in yard, new perfumes etc. she did have a reaction around the neckline ~2 mos ago after trying on a dress but that still doesn t explain the itching on her extremities. Fungus, scabies, mites? Some anti fungal cream behind knees just recently helped. Any suggestions? Thank you