Skin rash, reddish, round raised. scattered, only on my elbow.?

First of all...: "skin rash" is redundant -- the only place you can get a rash is on your skin. Second, without seeing it, all i can tell you is that psoriasis is commonly found on the elbows, as are a host of other dermatitides. You will have to get it examined in person to get a precise diagnosis.

Psoriasis or eczema?: Around the elbow, it is possible that this represents psoriasis or eczema but it could be a variety of other diseases , many of which may be easily treated or may require additional diagnostic tests.