The enlarged and painful lymph nodes of the whole body may be caused by the following diseases: Firstly, it may be viral infection or bacterial infection, which cannot be controlled and spreads to the whole body, resulting in systemic bacteremia or even sepsis, which can lead to irritating enlarged and painful lymph nodes of the whole body, and usually accompanied by persistent fever. Secondly, there may be systemic lymphoma, especially malignant lymphoma will appear this kind of symptom, usually the localized enlargement can not be detected by blood sampling, and it is necessary to do bone marrow aspiration to be able to make a clear diagnosis.