The causes of erythema all over the body one year after lymphoma autologous stem cell transplantation include local skin infection, allergic reaction, bleeding spots and so on. 1. Skin infection: after lymphoma autologous stem cell transplantation, the immunity of the patient’s body will be lowered, which will easily cause infection, such as skin infection. 2. Allergic reaction: when the patient comes into contact with allergens such as pollen, dust, feathers and other substances, allergic reactions such as spots will appear on the skin. 3. Bleeding spots: one year after autologous stem cell transplantation for lymphoma, the patient exists hypersplenism, which causes platelet lowering, thus bleeding manifestations, such as skin petechiae, ecchymosis, etc., will easily appear. In addition to the above reasons, the above situation may also appear after patients take certain drugs, such as drug rash appearing after taking penicillin, furazolidone and so on. It is recommended to go to the hospital in time, improve the examination to clarify the cause of the disease, and then give targeted treatment under the guidance of the physician.