How Can A Red And Itchy Rash On The Elbow Be Treated?

Hi, I ve had a persistent rash for over a year, that started out as a few red bumps I thought were a heat rash due to very hot weather in Texas. As time went on, the little red itchy watery filled bumps spread and will not go away no matter what I do (keep clean, use peroxide, alchohol, permethrin, anti-itch cream). It s located only on the inside elbow area of left arm, there is a 4 x 4 red patch now and the red bumps are mainly on the outside of red patch. It s itchy mostly in evening but also occurs during the day. I try not to scratch, but the only way to get relief of itch is to break the top layer of bump to release some watery fluid inside. I have had dogs for a long time and never in my life have experienced anything like this.