What Causes Redness On The Skin All Over The Body?

Hi,redness of the skin covering the whole body from head to toe,even in the scalp that is very dry and very itchy.tried several different lotions and skin moisturizers,had this spot to come up on shoulder a few years ago and got some kind of cream from doctor and it cleared it up.don't remember the name of the cream.this time it started on the same spot of the shoulder but has covered the whole body,the same cream as used before doesn't work this time and have found nothing so far that helps.also very nervous with this,82 year old male.