Children with bumps on the legs may be caused by atopic dermatitis, papular urticaria, keratosis pilaris and other causes. 1. Allergic dermatitis: children’s legs skin or mucous membranes in contact with fiber clothing and other allergic substances stimulation, may cause red bumps, and accompanied by intense itching. 2. Pemphigus urticaria: mosquito bites and other causes of pemphigus urticaria, manifested in clusters or scattered red, wind-bubble-like damage, and accompanied by a sense of itching. 3. Keratosis pilaris: it refers to the local keratinization or hyperplasia of the peripheral hairs to form keratinized pimples consistent with hair follicles, manifested by touching the pimples on the legs will feel solid, may be accompanied by a sense of itching. Children’s leg pimples should avoid scratching, if the pimples can not subside on their own, it is recommended that parents take their children to the hospital for diagnosis, to clarify the cause, and standardized treatment under the guidance of the doctor.