Patients with chronic mild leukopenia often have no specific symptoms. If non-specific symptoms such as fatigue, weakness, dizziness, loss of appetite and low fever occur, it is important to pay attention to routine blood tests, which are the only way to make an accurate diagnosis. Those with severe leukopenia, especially those with granulocyte deficiency, are prone to secondary infections, and may even develop sepsis, septicemia or infectious shock, leading to serious life-threatening consequences. The susceptibility to infection often varies from person to person and varies widely among individuals, and leukopenia is prone to frequent colds due to reduced resistance. The degree of leukopenia is not completely consistent with the infection and clinical presentation. Common infections include stomatitis, upper respiratory tract infections, bronchitis, pneumonia, otitis media, pyelonephritis or infections of the skin.