New Eczema in a 4 yr old?

[SomedayMyPrinceWillCome]

My DS is very nearly 4 and I think he has suddenly developed eczema. He has never had it before (even as a baby) and has no other allergies or sensitivities. He has developed a small patch of itchy dry skin on the inside of one of his elbows, it looks like the photos I have seen of eczema. He is otherwise extremely healthy.
Is it possible to develop it suddenly & relatively late?
I am treating it with E45, does this sound right?

Hopeful bump for the evening crew...?

I started getting exzema when I was about 7, and have always used e45. Funnily enough I got it on my elbows too, but on the outside. Never had it anywhere else and I grew out of it as I got into my late teens.

Saying that- I was never formally diagnosed. GPs did look at it when I went in for other things and just nodded when I said it was eczema but I suppose there is a possibility it was something else.