Hello, Welcome to healthcare magic. From your description, the possibilities of the rash on the extremities include nummular eczema or papular urticaria. While nummular eczema is a type of eczema, papular urticaria is a reaction to insect bites commonly mosquito bites. This is commonly seen in children who are predisposed to eczema. While cortisone cream will help in treating the rashes, remember that you cannot use it routinely . It is a mild steroid and has to be discontinued once the rashes subside. (2-3 weeks) To prevent recurrences, use a moisturizer twice a day. Use full arm shirts and trousers so that his extremities are covered and mosquito bites can be avoided. Hope this helps you. Take care.