Baby Has Rash Baby Has Rash All Over Body, What Would You Call It?

Baby has rash all over body, What would you call it? - baby has rash

I want a name for the onset of my children and I can not remember what was the doctor last time I described in my son's skin very sensitive and very dry winter and becomes a red rash, I tried to, tinted to little help to find, but I do not know what kind of rash is. Heat rash and saw everything they have is that in the summer, you do not believe is that it? Suggestions?