Children with hard bumps may be caused by hives, insect bites, boils, fibromas and other diseases, which need to be analyzed according to the symptoms. 1. urticaria: is due to a temporary increase in vascular permeability, resulting in limited edema, can cause skin tingling, itching, may cause the child body pimples hard. 2. Mosquito bites: mosquito bites caused by insect bite dermatitis, may also cause the bite site erythema, congestion, swelling, pain, itching, etc., can also lead to hard bumps on the child. 3. Boils: purulent infectious diseases in the deep part of the hair follicles and the surrounding tissues, early in the disease will cause hard nodules under the skin, accompanied by redness, swelling, pain, which will also lead to hard pimples on the child’s body. 4. Fibroma: abnormal proliferation of skin fibroblasts, resulting in benign tumors, manifested as hard nodules, will cause hard bumps on the skin, will also cause hard bumps on the child’s body. There may be other reasons for the hard bumps on your child’s body, and you need to go to the hospital in time to check and clarify the cause.