K.G.
M.,
It sounds like fifth disease. It is going around like crazy right now. Two of my children had it earlier this year. Body rash will be red and lace-like; similar to strep rash if you've ever seen that. Warm shower draws rash out so will look worse afterward. Rash will come and go for up to a month. Once rash appears, no longer contagious. Benadryl will not clear up rash. Typically looks much worse than is. Can be very dangerous exposure for pregnant women though. Good idea to have ped. confirm fifth disease though, especially since your son was sick and on med. not that long ago.