Why am i itchy?????????

So i have been itchy evrywher. Like my legs my arms my neck my face my hands my feet. I see some bumps on my hands and arms. Some bumps on my legs. After i scratch the area gets red and then i see bumps but they usualy go away. I ddnt kno if it was dry skin because thats what my brother said it might be, but my friends mom said it could be an allergic reaction. Please answer! Thanks!