What is meant by a connective tissue disease that is undifferentiated?
Undifferentiated connective tissue disease or UCTD refers to a disease of connective tissue that doesn't fit nicely in any one category of illness. They don't meet the exact diagnostic criteria of any one syndrome, rather signs and symptoms may overlap. Clinical and laboratory presentations may have similarities to other diseases. Most physicians only make a diagnosis of UCTD after the same signs and symptoms have been present for several years and other manifestations are absent. Sometimes UCTD is referred to as overlap syndrome or mixed connective tissue disease syndrome.
For example, a person may have some signs that point to rheumatoid arthritis and systemic lupus erythematosus at the same time but definitive diagnosis is not possible because of a lack of other defining characteristics.