Acute leukemia in children and adolescents has a rapid onset, with common first symptoms including fever, progressive anemia, significant bleeding tendencies, or bone and joint pain. The slow onset of acute leukemia is more common in elderly and some young patients, and the disease progresses gradually. In addition, a few patients may develop convulsions, blindness, toothache, swollen gums, pericardial effusion, and bilateral lower limb paraplegia as the first symptoms. The first symptom is fever, which is one of the most common symptoms of leukemia and manifests itself in different degrees of fever and pyrexia. The main cause of fever is infection, of which pharyngitis, stomatitis, and perianal infection are the most common. Pneumonia, tonsillitis, gingivitis, and perianal abscesses are also more common. Fever can also be a symptom of acute leukemia itself, without any signs of infection. The second is infection. Bacteria are the most common pathogens, and the likelihood of fungal infection gradually increases in the later stages of the disease due to prolonged below-normal granulocytes and the use of broad spectrum antibiotics. The third is bleeding, which can occur throughout the body, with skin, gum, and nasal bleeding being the most common, as well as bleeding from the retina, ears, gastrointestinal tract, respiratory tract, and other internal organs. There is also anemia, which can usually appear at an early stage. In a few cases, myelodysplastic syndromes can develop months or years before the diagnosis is made and then develop into leukemia. Then there is pain in bones and joints, enlargement of liver, spleen and lymph nodes, etc. The above is for reference only. Please refer to the doctor’s instructions for specific medication and treatment.