M.A.
My daughter has excema, and it's generally activated from sunblock or other creams/heat/sand (every time she plays in a sandbox), and she also has a sensitivity to eating fruit which breaks her face out. She's five now, and I use Baby Aquaphor on her face every day. After the rash clears up, try using it every day as a blocker--it's like vaseline. It works for us keeping her face clear and worked when she was a baby to keep her face/neck area clear. I also still wash her clothes separately and double rinse them as well as her linens.