I have this itching around my neck, thighs, upper arms, torso and it turns to reddish with tiny bumps. Some areas are just red with no bumps. Sometimes it is on my back and buttocks and groin. Is this some form of bacteria or virus.  I notice this only during the night after dinner and early morning after I shower, after breakfast. If it has anything to do with food, why it does not itch after lunch? The redness and bumps disappear after a few hours but the same process of itching continues during the night and morning! 

Please advise! I do have dry skin and seldom use any lotion as I do not like the oily feeling.