I started to get a itchy allergic rash on my body , its not too much but once i apply moisturizer its gone. im not sure if it dryness. how will i know!? its there for 20 min and it disappears after applying moisturizer. what could it be?

Rashes appear when you scratch your itchy dry skin, quite common during the winter after taking a warm shower. The itching due to allergic rashes may improve with moisturizer but rashes do not resolve right away after using moisturizer.

If it goes away after applying moisturizer only, it's probably not allergic in origin -- probably simple dry skin, which is common this time of year, when humidity is low. If you can solve the problem with moisturizer, I would just stick with that.