If you look up chlorine allergy and reactions, you get the same symptoms as mms which has chlorine component to it. But upon further research it isnt really an allergy per se. It is lack of ability by your body to detox chlorine. One of the cofactors needed to detox chlorine is taurine and if you take supplemental taurine you can cure your chlorine allergy. I think that since people are taking Miracle-Mineral-Supplement regularly they are depleting their taurine levels and it is causing the reaction.
So I tried taking taurine when I get itchy or hives from Miracle-Mineral-Supplement and it worked, they went away. That is my research and experience.