I am 50/f. itchy skin all over, no rash. benadryl (diphenhydramine) helps but puts me to sleep. skin does not seem dry. some weight gain. ?

Neurodermatitis?: It sounds like you may have Neurodermatitis however dry skin and other causes can not be excluded. If antihistamines help try a long acting non-sedating one like cetirizine or loratidine. Skin lotion also may be helpful. If the condition continues I recommend you see a dermatologist or allergist..

Get an: Evaluation . There are several things besides dry skin including thyroid disease that can cause your skin to itch all over . They can be treated.