How does lymphatic tuberculosis occur? Lymphatic tuberculosis is a disease that occurs in the lymphatic system after the body is infected with Mycobacterium tuberculosis. What are the characteristics of lymphatic tuberculosis? It starts slowly, with a lump like a bean at the beginning, the skin color remains unchanged, and it does not hurt or itch; later it gradually increases in size, and when it becomes pus, the skin color turns dark red, and after ulceration, the pus is clear and dilute, often healing and forming sinus tracts. Because it is common in the neck, the pus will break down and form a sinus tract. It is called “scrofula” in Chinese medicine, and is commonly called “scrofula neck” or “old rat sore” in folk medicine.