Can using Vinegar in Laundry cause Rashes?

I have come up with rashes in unusual places, it's really bad on the opposite of my elbows (the tendon area) also the front of my shoulders, near my arm pits and on my neck, but nowhere else! I barely scratch the rashes but they won't go away. So something must be causing my rashes to continue to flare up.

They started appearing around the same time I started to put vinegar in my laundry to substitute for softener...