What Causes Severe Rashes On Armpits Causing Burning Sensation?

Out of nowhere about a month ago, both my arm pitts started developing a severe rash with bumps and smelly seepage. I thought I was sweating without knowing so early on I tried zinc oxide and some fragrance free talcum but for the last couple weeks its been simply frequent washing, drying and airing as best I can but it became progressively worse. Tonigt its burning, I'm crying and finally my husband, the laundry guy, reveals that he changed detergents right about the time this started!! I can't plausibly think of anything else it could be... How can I heal this? It is severe.