That is an excellent question and one that is best answered by your primary care doctor
or a doctor specializing in RA such as an endocrinologist
. In general, there are several potential causes for why your ESR and CRP are normal while you are having inflammation in your esophagus and having normal signs of RA. One potential cause is that if you are taking medication to treat or control the RA, then it may be that for this reason the ESR and CRP are normal as your body is not mounting an inflammatory response and so these lab studies are normal. Another potential cause is that the samples are not taken during a flare up, and so your body may not be in the process of having inflammation and so these levels are not noted to be high. Regardless, if you have a clinical diagnosis of RA from a physician, then it is recommended that you follow their directions and if they suggest medications that you take those to help with the symptoms. Sometimes people do not always follow what is described in the textbooks so it may just be that you do not have elevations in ESR and CRP as would be expected in RA. It is recommended you discuss any further questions like this with your doctor.