Itchy blisters on children’s arms may be related to herpes simplex, eczema, contact dermatitis and other causes. 1. Herpes simplex: children’s arm skin is infected by the herpes simplex virus, which can be manifested as pain, itching and blisters on the arm, which can then rupture and form ulcers. 2. Eczema: caused by a variety of internal and external factors, itching intense inflammatory reaction of the skin, the rash is polymorphic, can appear papules or small blisters, often symmetrical distribution. 3. contact dermatitis: if a child’s arm skin contact with allergenic substances such as ointment, can cause the body to appear abnormal immune response, severe blisters can appear. There are many other reasons for children’s arm itchy blisters, it is recommended that parents take their children to the hospital in a timely manner to clarify the cause of the disease, standardized treatment under the guidance of the doctor.