Glad you are making the appointment- this must be really hard for you as well as your child, seeing them suffer so and not knowing how to stop the problem from happening!
NO FEVER,HAVE BEEN USING THE SAME DETERGENT, SOAPS AND SHAMPOOS SINCE BIRTH. WILL MAKE APPT. TO SEE DOC, THANKS FOR YOUR HELP
Does the toddler have a fever (could it be chicken pox, etc)?
Could your child be allergic to the detergent you use for your sheets and their pajamas or a lotion or soap, etc. (contact dermatitis rash)?
Could it be eczema or hives?
See private message & if you cannot pinpoint the cause, I hope you can get a quick appointment with the child's pediatrician!