Urticaria in children is not a sign of leukemia. Urticaria belongs to the skin diseases, is a kind of edematous mass confined to the surface of the skin and mucous membranes. The causes of urticaria are divided into exogenous and endogenous, exogenous including drug stimulation, food, drugs, exercise, etc., and endogenous including fatigue, mental stress, some autoimmune and chronic diseases. Urticaria can not be completely cured, most patients will have recurrent or prolonged episodes, and in severe cases, it will lead to respiratory obstruction, asphyxia or anaphylactic shock, but it is not found that urticaria will lead to leukemia, and there is no inevitable connection between the two. Leukemia is a class of hematopoietic system of malignant neoplastic diseases, causes of leukemia, including viral infections, immune function abnormalities, physical factors, chemical factors, genetic factors, etc., caused by the cause does not include urticaria. Therefore, urticaria in children is not a sign of leukemia.