Nosebleeds in two-year-olds may be related to dry air, acute leukemia, and thrombocytopenic purpura. 1. Dry air: when the indoor temperature is too high and humidity is low, it will lead to less moisture in the air and dry air. Two-year-old children’s nasal mucosa within the blood vessel wall is thinner than adults, brittle, dry air may lead to children’s nasal mucosa dry and blood vessel wall is more fragile, which leads to children’s nosebleed. 2. Acute leukemia: acute leukemia is due to the abnormal proliferation of primitive and naive cells in the bone marrow and inhibit normal hematopoiesis, mainly manifested as anemia, bleeding, etc., and bleeding symptoms can occur in all parts of the body, including nosebleeds, bleeding gums and so on. Therefore, when a two-year-old child has a nosebleed, you need to consider whether you have acute leukemia. 3. Thrombocytopenic purpura: Thrombocytopenic purpura is mainly manifested as ecchymosis and petechiae on the skin and mucous membranes, accompanied by bleeding in the nose and gums. When a child suffers from this disease, the symptoms of nosebleeds are likely to occur. When a two-year-old child has a nosebleed, he or she should seek medical attention in a timely manner to have the cause clarified and treated by a medical professional.