My 3 year old got a rash on her face, neck, and upper chest and back. It was light colored but splochy red. There were a lot of tiny bumps - the doctor described them as "sandpaper-y". We gave her benadryl and it didn't do anything for her. we took her to the emergency room where they did a cbc and strep test. (Keeping in mind that my kids are not in school / daycare. I stay at home with them every day, and nobody in the house has been sick.) My daughter's strep test came back very positive - the doc explained that the rash was Scarlatina - a bacterial problem caused by the strep. She hasn't complained of sore throat, no cough, very little fever (nothing above 100* F). The only issues with her were the rash - slight itching, and just seeming tired. Take your son to the doctor.
Hello,
Due to the suddenness of appearance of rash along with no prior history of any rash,it can be due to a viral infection or an allergic reaction.Scarlet fever(strep infection with a rash) and other viral infections and allergic reaction due to contact dermatitis have to be ruled out.Apply calamine lotion on the rash and consult a pediatrician soon.Treatment for all is different and before prescribing any medicine in children ,it is important to confirm a diagnosis first.
Hope it helps.Take care and pls do keep me posted.