A complete medical evaluation is very necessary for diagnosing your condition. Itchy red bumps on legs, arms and stomach can be due to any allergy, inflammation or infection. It is possible that it is urticaria or contact dermatitis which might have occurred after contact with any allergen which can be in food, clothing or in the environment. Take an antihistamine like hydroxyzine.If it is allergic in nature then it will respond to antihistamines. Another possibility is scabies caused by Sarcoptes scabiei in which there are rashes, itching and sores on the skin from scratching and digging. A clinical examination is necessary for complete diagnosis and management. Do keep me posted.
Best wishes and regards!