Itching due to insect bites, rashes and chicken pox can be treated with Benadryl Elixir. This can be given every four hours as needed. It is also a good idea to trim fingernails to protect the skin from scarring. A very common rash that causes itching is eczema, an allergic rash. Small bumps on the skin can be due to an infestation of a small insect. This condition is called Scabies. Children that have itching for more than just a few days should have an office visit to determine the cause.