Eczema is another name for dermatitis (inflammation of the skin). It comes in many forms. Sometimes, it comes in a circular fashion (thus easily be confused with “ring worm” tinea infection). A circular form of eczema is called “discoid eczema”. A common site for discoid eczema to occur is on the back of the neck. After having been rubbed for many months, the skin in that area would start to thicken up, giving the slightly lumpy appearance shown in this photo.
I often hear parents asking their child, wife asking her husband (and vice versa), not to scratch. This is like the British royal family trying to censor the Chasers over their royal wedding coverage , a futile excercise.