Where ever it gets itchy in random spots and i scrath and it turns into a big yellow bump, do you think its an allergic reaction?!

? eczema: Or an itch that rashes, you probably have dry skin too, or you may have dermatographism, a kind of physical urticaria, we need to know more information and you need to be examined, kindly see your doctor who might refer you to a dermatologist/allergist, meanwhile keep yourself well hydrated, use cream soap while bathing and moisturize your skin well right after,