Babies always slap their heads may be caused by insect bite reaction, infantile eczema, purulent meningitis and other diseases. 1. Insect bite reaction: If the head of the affected child is bitten by insects, such as mosquitoes, lice, fleas, etc., which causes an allergic skin reaction, resulting in localized itching, erythema and other symptoms, but because the child is young and can’t speak, he or she expresses the discomfort by slapping his or her head. 2. Infantile eczema: the cause of this disease is not clear, it may be related to heredity, early addition of complementary foods, excessive washing and care of the skin and other reasons. Prevalent areas include cheeks and head, etc. Localized itching and pimples will appear, and children often beat their heads due to excessive itching. 3. Purulent meningitis: the common causative organisms of this disease are Streptococcus pneumoniae and Dictyostelium meningitidis, etc. It is possible that the infection in the ear, nose, etc. may invade the brain tissues through the blood circulation and direct spread, etc. The main symptoms include high fever, chills, severe headache, local or generalized convulsions, etc., which may be manifested as the child’s always patting his head. The baby is always tapping his head, there may be other reasons, it is recommended to go to the hospital in time, improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.