There are a few different possible causes of these bumps. If they persist or spread, you should definitely see your primary care doctor
about them. Also, if they are very itchy or painful, your doctor will be able to suggest to you which medications you might use to relieve the symptoms.
One of the most likely causes is eczema
, which is a condition in which areas of the skin become reddened and dried out. This is generally quite itchy, but it may be more "irritated" if the involved skin is rubbing against clothing or another surface.
If the reddened areas are less patch-like and more confined to small, raised circles, then another possibility is that these are bug bites of one sort or another. Bug bites often can be quite red and itchy or painful, and this may be worse if you scratch them. There are a number of different bugs that could be causing the bites, including bed bugs, spiders, and fleas.
Your doctor can examine your skin and tell you whether this is a bite, eczema, or another condition all together. There are excellent prescription creams that can be used to treat skin itching or inflammation, and your doctor may prescribe one of these for you if necessary.