Dr. Joseph Murray, of the Mayo Clinic Rochester, MN, is a gastroenterologist who specializes in treating Celiac disease. Dr. Murray gave us the standard definition of celiac disease: celiac disease is a permanent intolerance to gluten that results in damage to the intestine and is reversible with avoidance of dietary gluten. There are some important parts in this definition:
Permanent: The effects of celiac disease may change from time to time. You may be sicker at one phase of your life than at another. For example, you may be sicker at age two, may seem to get better during the teenage years, may be sick again in your 20s (but with different symptoms), and then present with bone problems when you are in your 50s. So there may be different phases, but it is a PERMANENT intolerance. You do NOT outgrow it; you do not go through phases where you dont have it anymore. (That used to be what was thought and TAUGHT in medical schools.).
Damage to the intestine: There is definitely intestinal damage; without it you cannot define . For some people the damage is severe, for others it is not so severe. It is the cases which are not so severe that can be difficult to diagnose. If the damage is mild then the person interpreting the biopsy might not even think of celiac disease as being a possible cause of the damage.
Reversible: The damage should be reversible. Dr. Murray says there are about 5% of people with what he believes is celiac disease in whom at one point in their lives the damage becomes irreversible. In these cases there is intestinal damage that does not completely recover. It may partially heal, but not completely. One can infer that they have the same condition as celiacs that do recover, based on their history. There may be something different about that group of patients in their immune systems that makes them different, but that is an area that is still being actively researched.