A child’s fever once a month is a sign of low immunity, which can usually be caused by poor physical condition, illness and other reasons. 1. Poor physical quality: the most common situation, the child may not like sports, picky eaters, lack of sleep and other reasons, resulting in poor physical quality, the resistance to external pathogens is not strong, resulting in easy to infect and cause fever. 2. Suffering from diseases: when suffering from some chronic diseases, it will also make the child’s immunity decline. Such as iron deficiency anemia, nephrotic syndrome, due to the body’s material metabolism and other aspects of the abnormalities, so that the resistance to decline; with leukemia, etc., directly to the body immunity decline. Disease-induced immunity decline can also have other symptoms, such as iron deficiency anemia can be pale; nephrotic syndrome can be edema, etc., parents should carefully observe the child’s situation, if necessary, can go to the hospital for treatment.