if the itch is truly " all over your body" then the cause is most likely an allergic reaction to something you may have eaten breathed taken medically or touched. i know that doesn't narrow down the field but finding the one (or more) possible sources of generalized itching can be very very difficult. start with new things. things you may have touched including soaps laundry detergents or chemical spays. then scrutize any new foods or new medications you are taking. a longer-lasting antihistamine (zyrtec claritin) may be helpful but it is still okay to take the benadryl if you want as long as you take it regularly. if things to not settle down for you you will need to consult or see your medical provider.
i have an itch all over my body. it is an intense itch almost painful at times. i took benadryl last night and have aveeno cream but its back.