Erythroblastosis is a myeloproliferative disorder characterized by clonal erythropoiesis. It is prevalent in middle-aged and elderly men, with insidious onset and occasional detection on physical examination. Increased blood viscosity can lead to slow blood flow and tissue hypoxia, manifested as headache, dizziness, excessive sweating, fatigue, forgetfulness, tinnitus, blurred vision, visual impairment, numbness and tingling in the extremities. When accompanied by thrombocytosis, there may be thrombosis and infarction, commonly in the extremities, mesentery, brain and coronary vessels, and in severe cases, paralysis. When basophilia is increased, basophilic granules rich in histamine are released in large quantities to stimulate the cells of the gastric gland wall, which can lead to peptic ulcers, and irritation of the skin can have obvious pruritus.