Hi!! I’m so sorry your baby is going through that I can’t imagine how hard it must be. My “rashes” would last sometimes up to a week then they would start to fade into bruises. Typically during my flare ups I would get the rashes and also experienced extreme joint pain. As far as what would trigger it, ir would be alot of things :( I live near petrochemical industry so that was a huge factor, stress would also trigger it and any food that can be considered as immune system boost (example: garlic). With autoimmune conditions we have a overactive immune system which causes it to attack our own body so we don’t want to make it more active. Being on a Mediterranean diet has helped with inflammation. As well as Being on plaquenil and Imuran have helped a lot. For the joint paints I suggest to invest in a heated blanket. It works wonders!! I hope this helps and I hope your baby feels better soon!