I use Seventh Generation Free and Clear 2X Concentrated Laundry Detergent. It can be used in both regular and High Efficency washers. I use it because I have Severe Multiple Chemical Sensitivities and am allergic to most everything, too. It works really well for me.
I'm sorry to hear about your son's eczema. One of my DGD was just diagnosed with it. I hope you find something that works for you. :)